Assume C99 or later.

* lib/stdarg.in.h, lib/stdbool.in.h, m4/stdarg.m4, m4/stdbool.m4:
Remove.
* configure.ac (_AC_PROG_CC_C89): Define a dummy, to keep 'configure'
smaller.
(gl_PROG_CC_C99): Use this to get C99 or later.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* admin/merge-gnulib (GNULIB_MODULES): Remove stdarg, stdbool.
(GNULIB_TOOL_FLAGS): Avoid stdarg, stdbool.
* doc/lispref/internals.texi (C Dialect): Document this.
* etc/NEWS: Document this.
* nt/gnulib.mk: Remove stdarg and stdbool modules.
* src/bytecode.c (B__dummy__): Remove.
* src/conf_post.h (bool_bf) [!NS_IMPL_GNUSTEP]: Use bool.
(FLEXIBLE_ARRAY_MEMBER): Now always empty.
* src/dbusbind.c (XD_DEBUG_MESSAGE) [!DBUS_DEBUG]:
* src/regex.c (DEBUG_PRINT): Assume varargs macros.
* src/lisp.h (DEFUN_FUNCTION_INIT): Remove.  All uses now assume C99.

Fixes: debbugs:17487

23 files changed, 71 insertions, 501 deletions

diff --git a/ChangeLog b/ChangeLog
index 70e7de030d2..39dee67f7ec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Assume C99 or later (Bug#17487).
+        * lib/stdarg.in.h, lib/stdbool.in.h, m4/stdarg.m4, m4/stdbool.m4:
+        Remove.
+        * configure.ac (_AC_PROG_CC_C89): Define a dummy, to keep 'configure'
+        smaller.
+        (gl_PROG_CC_C99): Use this to get C99 or later.
+        * lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
+
 2014-05-16  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't require pkg-config when building from repository.
diff --git a/admin/ChangeLog b/admin/ChangeLog
index 0981e0eaf10..3d8b21ff144 100644
--- a/admin/ChangeLog
+++ b/admin/ChangeLog
@@ -1,3 +1,9 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Assume C99 or later (Bug#17487).
+        * merge-gnulib (GNULIB_MODULES): Remove stdarg, stdbool.
+        (GNULIB_TOOL_FLAGS): Avoid stdarg, stdbool.
+
 2014-05-16  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't require pkg-config when building from repository.
diff --git a/admin/merge-gnulib b/admin/merge-gnulib
index b93d12fbd20..5df2020f3aa 100755
--- a/admin/merge-gnulib
+++ b/admin/merge-gnulib
@@ -35,7 +35,7 @@ GNULIB_MODULES='
   intprops largefile lstat
   manywarnings memrchr mkostemp mktime
   pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat
-  sig2str socklen stat-time stdalign stdarg stdbool stdio
+  sig2str socklen stat-time stdalign stdio
   strftime strtoimax strtoumax symlink sys_stat
   sys_time time timer-time timespec-add timespec-sub
   unsetenv update-copyright utimens
@@ -49,6 +49,7 @@ GNULIB_TOOL_FLAGS='
   --avoid=open --avoid=openat-die --avoid=opendir
   --avoid=raise
   --avoid=save-cwd --avoid=select --avoid=sigprocmask
+  --avoid=stdarg --avoid=stdbool
   --avoid=threadlib
   --conditional-dependencies --import --no-changelog --no-vc-files
   --makefile-name=gnulib.mk
diff --git a/configure.ac b/configure.ac
index 55e5b8c0b5f..0119685394b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -670,6 +670,9 @@ fi
 
 #### Choose a compiler.
 
+dnl Don't bother to test for C89.
+AC_DEFUN([_AC_PROG_CC_C89], [$2])
+
 dnl Sets GCC=yes if using gcc.
 AC_PROG_CC([gcc cc cl clang "$XCRUN gcc" "$XCRUN clang"])
 if test -n "$XCRUN"; then
@@ -677,6 +680,9 @@ if test -n "$XCRUN"; then
   test -n "$AR" && export AR
 fi
 
+dnl Emacs needs C99 or later.
+gl_PROG_CC_C99
+
 AM_PROG_CC_C_O
 
 if test x$GCC = xyes; then
@@ -1303,7 +1309,7 @@ else
   CPPFLAGS="$C_SWITCH_SYSTEM $C_SWITCH_MACHINE $CPPFLAGS"
 fi
 
-# Suppress obsolescent Autoconf test for size_t; Emacs assumes C89 or better.
+# Suppress obsolescent Autoconf test for size_t; Emacs assumes C99 or better.
 AC_DEFUN([AC_TYPE_SIZE_T])
 # Likewise for obsolescent test for uid_t, gid_t; Emacs assumes them.
 AC_DEFUN([AC_TYPE_UID_T])
diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 7d85e4059c9..d892e1307a0 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Assume C99 or later (Bug#17487).
+        * internals.texi (C Dialect): Document this.
+
 2014-05-15  Dmitry Antipov  <dmantipov@yandex.ru>
 
         * lists.texi (Building Cons Cells and Lists): Remove
diff --git a/doc/lispref/internals.texi b/doc/lispref/internals.texi
index bfc9d491c5e..3a5bd4aea7e 100644
--- a/doc/lispref/internals.texi
+++ b/doc/lispref/internals.texi
@@ -580,15 +580,14 @@ Emacs session.
 @section C Dialect
 @cindex C programming language
 
-The C part of Emacs is portable to C89: C99-specific features such as
-@samp{<stdbool.h>} and @samp{inline} are not used without a check,
+The C part of Emacs is portable to C99 or later: C11-specific features such
+as @samp{<stdalign.h>} and @samp{_Noreturn} are not used without a check,
 typically at configuration time, and the Emacs build procedure
-provides a substitute implementation if necessary.  Some C99 features,
-such as declarations after statements, are too difficult to provide
-substitutes for, so they are avoided entirely.
+provides a substitute implementation if necessary.  Some C11 features,
+such as anonymous structures and unions, are too difficult to emulate,
+so they are avoided entirely.
 
-At some point in the not-too-distant future the base C dialect will
-change from C89 to C99, and eventually it will no doubt change to C11.
+At some point in the future the base C dialect will no doubt change to C11.
 
 @node Writing Emacs Primitives
 @section Writing Emacs Primitives
diff --git a/etc/ChangeLog b/etc/ChangeLog
index 80f3bf54a11..5a359e02863 100644
--- a/etc/ChangeLog
+++ b/etc/ChangeLog
@@ -1,3 +1,7 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * NEWS: Assume C99 or later (Bug#17487).
+
 2014-05-16  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't require pkg-config when building from repository.
diff --git a/etc/NEWS b/etc/NEWS
index cfee11e5917..f14fab3faea 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -25,6 +25,8 @@ otherwise leave it unmarked.
 * Installation Changes in Emacs 24.5
 
 +++
+** Building Emacs now requires C99 or later.
+
 ** Building Emacs now requires GNU make.
 
 ** By default, Emacs no longer works on IRIX.  We expect that Emacs
diff --git a/lib/gnulib.mk b/lib/gnulib.mk
index e219292aa34..231b38dbf03 100644
--- a/lib/gnulib.mk
+++ b/lib/gnulib.mk
@@ -21,7 +21,7 @@
 # the same distribution terms as the rest of that program.
 #
 # Generated by gnulib-tool.
-# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt byteswap c-ctype c-strcase careadlinkat close-stream count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdarg stdbool stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv update-copyright utimens warnings
+# Reproduce by: gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --avoid=close --avoid=dup --avoid=fchdir --avoid=fstat --avoid=malloc-posix --avoid=msvc-inval --avoid=msvc-nothrow --avoid=open --avoid=openat-die --avoid=opendir --avoid=raise --avoid=save-cwd --avoid=select --avoid=sigprocmask --avoid=stdarg --avoid=stdbool --avoid=threadlib --makefile-name=gnulib.mk --conditional-dependencies --no-libtool --macro-prefix=gl --no-vc-files alloca-opt byteswap c-ctype c-strcase careadlinkat close-stream count-one-bits count-trailing-zeros crypto/md5 crypto/sha1 crypto/sha256 crypto/sha512 dtoastr dtotimespec dup2 environ execinfo faccessat fcntl fcntl-h fdatasync fdopendir filemode fstatat fsync getloadavg getopt-gnu gettime gettimeofday intprops largefile lstat manywarnings memrchr mkostemp mktime pipe2 pselect pthread_sigmask putenv qacl readlink readlinkat sig2str socklen stat-time stdalign stdio strftime strtoimax strtoumax symlink sys_stat sys_time time timer-time timespec-add timespec-sub unsetenv update-copyright utimens warnings
 
 
 MOSTLYCLEANFILES += core *.stackdump
@@ -900,57 +900,6 @@ EXTRA_DIST += stdalign.in.h
 
 ## end   gnulib module stdalign
 
-## begin gnulib module stdarg
-
-BUILT_SOURCES += $(STDARG_H)
-
-# We need the following in order to create <stdarg.h> when the system
-# doesn't have one that works with the given compiler.
-if GL_GENERATE_STDARG_H
-stdarg.h: stdarg.in.h $(top_builddir)/config.status
-        $(AM_V_GEN)rm -f $@-t $@ && \
-        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
-          sed -e 's|@''GUARD_PREFIX''@|GL|g' \
-              -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
-              -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
-              -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
-              -e 's|@''NEXT_STDARG_H''@|$(NEXT_STDARG_H)|g' \
-              < $(srcdir)/stdarg.in.h; \
-        } > $@-t && \
-        mv $@-t $@
-else
-stdarg.h: $(top_builddir)/config.status
-        rm -f $@
-endif
-MOSTLYCLEANFILES += stdarg.h stdarg.h-t
-
-EXTRA_DIST += stdarg.in.h
-
-## end   gnulib module stdarg
-
-## begin gnulib module stdbool
-
-BUILT_SOURCES += $(STDBOOL_H)
-
-# We need the following in order to create <stdbool.h> when the system
-# doesn't have one that works.
-if GL_GENERATE_STDBOOL_H
-stdbool.h: stdbool.in.h $(top_builddir)/config.status
-        $(AM_V_GEN)rm -f $@-t $@ && \
-        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-          sed -e 's/@''HAVE__BOOL''@/$(HAVE__BOOL)/g' < $(srcdir)/stdbool.in.h; \
-        } > $@-t && \
-        mv $@-t $@
-else
-stdbool.h: $(top_builddir)/config.status
-        rm -f $@
-endif
-MOSTLYCLEANFILES += stdbool.h stdbool.h-t
-
-EXTRA_DIST += stdbool.in.h
-
-## end   gnulib module stdbool
-
 ## begin gnulib module stddef
 
 BUILT_SOURCES += $(STDDEF_H)
diff --git a/lib/stdarg.in.h b/lib/stdarg.in.h
deleted file mode 100644
index 5b37dd3601a..00000000000
--- a/lib/stdarg.in.h
+++ /dev/null
@@ -1,35 +0,0 @@
-/* Substitute for and wrapper around <stdarg.h>.
-   Copyright (C) 2008-2014 Free Software Foundation, Inc.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
-
-#ifndef _@GUARD_PREFIX@_STDARG_H
-
-#if __GNUC__ >= 3
-@PRAGMA_SYSTEM_HEADER@
-#endif
-@PRAGMA_COLUMNS@
-
-/* The include_next requires a split double-inclusion guard.  */
-#@INCLUDE_NEXT@ @NEXT_STDARG_H@
-
-#ifndef _@GUARD_PREFIX@_STDARG_H
-#define _@GUARD_PREFIX@_STDARG_H
-
-#ifndef va_copy
-# define va_copy(a,b) ((a) = (b))
-#endif
-
-#endif /* _@GUARD_PREFIX@_STDARG_H */
-#endif /* _@GUARD_PREFIX@_STDARG_H */
diff --git a/lib/stdbool.in.h b/lib/stdbool.in.h
deleted file mode 100644
index 651e8dffdb3..00000000000
--- a/lib/stdbool.in.h
+++ /dev/null
@@ -1,132 +0,0 @@
-/* Copyright (C) 2001-2003, 2006-2014 Free Software Foundation, Inc.
-   Written by Bruno Haible <haible@clisp.cons.org>, 2001.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
-
-#ifndef _GL_STDBOOL_H
-#define _GL_STDBOOL_H
-
-/* ISO C 99 <stdbool.h> for platforms that lack it.  */
-
-/* Usage suggestions:
-
-   Programs that use <stdbool.h> should be aware of some limitations
-   and standards compliance issues.
-
-   Standards compliance:
-
-       - <stdbool.h> must be #included before 'bool', 'false', 'true'
-         can be used.
-
-       - You cannot assume that sizeof (bool) == 1.
-
-       - Programs should not undefine the macros bool, true, and false,
-         as C99 lists that as an "obsolescent feature".
-
-   Limitations of this substitute, when used in a C89 environment:
-
-       - <stdbool.h> must be #included before the '_Bool' type can be used.
-
-       - You cannot assume that _Bool is a typedef; it might be a macro.
-
-       - Bit-fields of type 'bool' are not supported.  Portable code
-         should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'.
-
-       - In C99, casts and automatic conversions to '_Bool' or 'bool' are
-         performed in such a way that every nonzero value gets converted
-         to 'true', and zero gets converted to 'false'.  This doesn't work
-         with this substitute.  With this substitute, only the values 0 and 1
-         give the expected result when converted to _Bool' or 'bool'.
-
-       - C99 allows the use of (_Bool)0.0 in constant expressions, but
-         this substitute cannot always provide this property.
-
-   Also, it is suggested that programs use 'bool' rather than '_Bool';
-   this isn't required, but 'bool' is more common.  */
-
-
-/* 7.16. Boolean type and values */
-
-/* BeOS <sys/socket.h> already #defines false 0, true 1.  We use the same
-   definitions below, but temporarily we have to #undef them.  */
-#if defined __BEOS__ && !defined __HAIKU__
-# include <OS.h> /* defines bool but not _Bool */
-# undef false
-# undef true
-#endif
-
-#ifdef __cplusplus
-# define _Bool bool
-# define bool bool
-#else
-# if defined __BEOS__ && !defined __HAIKU__
-  /* A compiler known to have 'bool'.  */
-  /* If the compiler already has both 'bool' and '_Bool', we can assume they
-     are the same types.  */
-#  if !@HAVE__BOOL@
-typedef bool _Bool;
-#  endif
-# else
-#  if !defined __GNUC__
-   /* If @HAVE__BOOL@:
-        Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when
-        the built-in _Bool type is used.  See
-          http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
-          http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
-          http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html
-        Similar bugs are likely with other compilers as well; this file
-        wouldn't be used if <stdbool.h> was working.
-        So we override the _Bool type.
-      If !@HAVE__BOOL@:
-        Need to define _Bool ourselves. As 'signed char' or as an enum type?
-        Use of a typedef, with SunPRO C, leads to a stupid
-          "warning: _Bool is a keyword in ISO C99".
-        Use of an enum type, with IRIX cc, leads to a stupid
-          "warning(1185): enumerated type mixed with another type".
-        Even the existence of an enum type, without a typedef,
-          "Invalid enumerator. (badenum)" with HP-UX cc on Tru64.
-        The only benefit of the enum, debuggability, is not important
-        with these compilers.  So use 'signed char' and no enum.  */
-#   define _Bool signed char
-#  else
-   /* With this compiler, trust the _Bool type if the compiler has it.  */
-#   if !@HAVE__BOOL@
-   /* For the sake of symbolic names in gdb, define true and false as
-      enum constants, not only as macros.
-      It is tempting to write
-         typedef enum { false = 0, true = 1 } _Bool;
-      so that gdb prints values of type 'bool' symbolically.  But then
-      values of type '_Bool' might promote to 'int' or 'unsigned int'
-      (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int'
-      (see ISO C 99 6.3.1.1.(2)).  So add a negative value to the
-      enum; this ensures that '_Bool' promotes to 'int'.  */
-typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
-#   endif
-#  endif
-# endif
-# define bool _Bool
-#endif
-
-/* The other macros must be usable in preprocessor directives.  */
-#ifdef __cplusplus
-# define false false
-# define true true
-#else
-# define false 0
-# define true 1
-#endif
-
-#define __bool_true_false_are_defined 1
-
-#endif /* _GL_STDBOOL_H */
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 0ba2d7950af..98acc069c92 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -119,13 +119,6 @@ AC_DEFUN([gl_EARLY],
   # Code from module stat:
   # Code from module stat-time:
   # Code from module stdalign:
-  # Code from module stdarg:
-  dnl Some compilers (e.g., AIX 5.3 cc) need to be in c99 mode
-  dnl for the builtin va_copy to work.  With Autoconf 2.60 or later,
-  dnl gl_PROG_CC_C99 arranges for this.  With older Autoconf gl_PROG_CC_C99
-  dnl shouldn't hurt, though installers are on their own to set c99 mode.
-  gl_PROG_CC_C99
-  # Code from module stdbool:
   # Code from module stddef:
   # Code from module stdint:
   # Code from module stdio:
@@ -342,8 +335,6 @@ AC_DEFUN([gl_INIT],
   gl_STAT_TIME
   gl_STAT_BIRTHTIME
   gl_STDALIGN_H
-  gl_STDARG_H
-  AM_STDBOOL_H
   gl_STDDEF_H
   gl_STDINT_H
   gl_STDIO_H
@@ -891,8 +882,6 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/stat-time.h
   lib/stat.c
   lib/stdalign.in.h
-  lib/stdarg.in.h
-  lib/stdbool.in.h
   lib/stddef.in.h
   lib/stdint.in.h
   lib/stdio.in.h
@@ -998,8 +987,6 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/stat-time.m4
   m4/stat.m4
   m4/stdalign.m4
-  m4/stdarg.m4
-  m4/stdbool.m4
   m4/stddef_h.m4
   m4/stdint.m4
   m4/stdio_h.m4
diff --git a/m4/stdarg.m4 b/m4/stdarg.m4
deleted file mode 100644
index 732aa313b6a..00000000000
--- a/m4/stdarg.m4
+++ /dev/null
@@ -1,78 +0,0 @@
-# stdarg.m4 serial 6
-dnl Copyright (C) 2006, 2008-2014 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl From Bruno Haible.
-dnl Provide a working va_copy in combination with <stdarg.h>.
-
-AC_DEFUN([gl_STDARG_H],
-[
-  STDARG_H=''
-  NEXT_STDARG_H='<stdarg.h>'
-  AC_MSG_CHECKING([for va_copy])
-  AC_CACHE_VAL([gl_cv_func_va_copy], [
-    AC_COMPILE_IFELSE(
-      [AC_LANG_PROGRAM(
-         [[#include <stdarg.h>]],
-         [[
-#ifndef va_copy
-void (*func) (va_list, va_list) = va_copy;
-#endif
-         ]])],
-      [gl_cv_func_va_copy=yes],
-      [gl_cv_func_va_copy=no])])
-  AC_MSG_RESULT([$gl_cv_func_va_copy])
-  if test $gl_cv_func_va_copy = no; then
-    dnl Provide a substitute.
-    dnl Usually a simple definition in <config.h> is enough. Not so on AIX 5
-    dnl with some versions of the /usr/vac/bin/cc compiler. It has an <stdarg.h>
-    dnl which does '#undef va_copy', leading to a missing va_copy symbol. For
-    dnl this platform, we use an <stdarg.h> substitute. But we cannot use this
-    dnl approach on other platforms, because <stdarg.h> often defines only
-    dnl preprocessor macros and gl_ABSOLUTE_HEADER, gl_CHECK_NEXT_HEADERS do
-    dnl not work in this situation.
-    AC_EGREP_CPP([vaccine],
-      [#if defined _AIX && !defined __GNUC__
-        AIX vaccine
-       #endif
-      ], [gl_aixcc=yes], [gl_aixcc=no])
-    if test $gl_aixcc = yes; then
-      dnl Provide a substitute <stdarg.h> file.
-      STDARG_H=stdarg.h
-      gl_NEXT_HEADERS([stdarg.h])
-      dnl Fallback for the case when <stdarg.h> contains only macro definitions.
-      if test "$gl_cv_next_stdarg_h" = '""'; then
-        gl_cv_next_stdarg_h='"///usr/include/stdarg.h"'
-        NEXT_STDARG_H="$gl_cv_next_stdarg_h"
-      fi
-    else
-      dnl Provide a substitute in <config.h>, either __va_copy or as a simple
-      dnl assignment.
-      gl_CACHE_VAL_SILENT([gl_cv_func___va_copy], [
-        AC_COMPILE_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[#include <stdarg.h>]],
-             [[
-#ifndef __va_copy
-error, bail out
-#endif
-             ]])],
-          [gl_cv_func___va_copy=yes],
-          [gl_cv_func___va_copy=no])])
-      if test $gl_cv_func___va_copy = yes; then
-        AC_DEFINE([va_copy], [__va_copy],
-          [Define as a macro for copying va_list variables.])
-      else
-        AH_VERBATIM([gl_VA_COPY], [/* A replacement for va_copy, if needed.  */
-#define gl_va_copy(a,b) ((a) = (b))])
-        AC_DEFINE([va_copy], [gl_va_copy],
-          [Define as a macro for copying va_list variables.])
-      fi
-    fi
-  fi
-  AC_SUBST([STDARG_H])
-  AM_CONDITIONAL([GL_GENERATE_STDARG_H], [test -n "$STDARG_H"])
-  AC_SUBST([NEXT_STDARG_H])
-])
diff --git a/m4/stdbool.m4 b/m4/stdbool.m4
deleted file mode 100644
index 006ed52de5d..00000000000
--- a/m4/stdbool.m4
+++ /dev/null
@@ -1,100 +0,0 @@
-# Check for stdbool.h that conforms to C99.
-
-dnl Copyright (C) 2002-2006, 2009-2014 Free Software Foundation, Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-#serial 5
-
-# Prepare for substituting <stdbool.h> if it is not supported.
-
-AC_DEFUN([AM_STDBOOL_H],
-[
-  AC_REQUIRE([AC_CHECK_HEADER_STDBOOL])
-
-  # Define two additional variables used in the Makefile substitution.
-
-  if test "$ac_cv_header_stdbool_h" = yes; then
-    STDBOOL_H=''
-  else
-    STDBOOL_H='stdbool.h'
-  fi
-  AC_SUBST([STDBOOL_H])
-  AM_CONDITIONAL([GL_GENERATE_STDBOOL_H], [test -n "$STDBOOL_H"])
-
-  if test "$ac_cv_type__Bool" = yes; then
-    HAVE__BOOL=1
-  else
-    HAVE__BOOL=0
-  fi
-  AC_SUBST([HAVE__BOOL])
-])
-
-# AM_STDBOOL_H will be renamed to gl_STDBOOL_H in the future.
-AC_DEFUN([gl_STDBOOL_H], [AM_STDBOOL_H])
-
-# This version of the macro is needed in autoconf <= 2.68.
-
-AC_DEFUN([AC_CHECK_HEADER_STDBOOL],
-  [AC_CACHE_CHECK([for stdbool.h that conforms to C99],
-     [ac_cv_header_stdbool_h],
-     [AC_COMPILE_IFELSE(
-        [AC_LANG_PROGRAM(
-           [[
-             #include <stdbool.h>
-             #ifndef bool
-              "error: bool is not defined"
-             #endif
-             #ifndef false
-              "error: false is not defined"
-             #endif
-             #if false
-              "error: false is not 0"
-             #endif
-             #ifndef true
-              "error: true is not defined"
-             #endif
-             #if true != 1
-              "error: true is not 1"
-             #endif
-             #ifndef __bool_true_false_are_defined
-              "error: __bool_true_false_are_defined is not defined"
-             #endif
-
-             struct s { _Bool s: 1; _Bool t; } s;
-
-             char a[true == 1 ? 1 : -1];
-             char b[false == 0 ? 1 : -1];
-             char c[__bool_true_false_are_defined == 1 ? 1 : -1];
-             char d[(bool) 0.5 == true ? 1 : -1];
-             /* See body of main program for 'e'.  */
-             char f[(_Bool) 0.0 == false ? 1 : -1];
-             char g[true];
-             char h[sizeof (_Bool)];
-             char i[sizeof s.t];
-             enum { j = false, k = true, l = false * true, m = true * 256 };
-             /* The following fails for
-                HP aC++/ANSI C B3910B A.05.55 [Dec 04 2003]. */
-             _Bool n[m];
-             char o[sizeof n == m * sizeof n[0] ? 1 : -1];
-             char p[-1 - (_Bool) 0 < 0 && -1 - (bool) 0 < 0 ? 1 : -1];
-             /* Catch a bug in an HP-UX C compiler.  See
-                http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
-                http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
-              */
-             _Bool q = true;
-             _Bool *pq = &q;
-           ]],
-           [[
-             bool e = &s;
-             *pq |= q;
-             *pq |= ! q;
-             /* Refer to every declared value, to avoid compiler optimizations.  */
-             return (!a + !b + !c + !d + !e + !f + !g + !h + !i + !!j + !k + !!l
-                     + !m + !n + !o + !p + !q + !pq);
-           ]])],
-        [ac_cv_header_stdbool_h=yes],
-        [ac_cv_header_stdbool_h=no])])
-   AC_CHECK_TYPES([_Bool])
-])
diff --git a/nt/ChangeLog b/nt/ChangeLog
index fc1b0a09102..a3cb5e62dac 100644
--- a/nt/ChangeLog
+++ b/nt/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Assume C99 or later (Bug#17487).
+        * gnulib.mk: Remove stdarg and stdbool modules.
+
 2014-05-16  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't require pkg-config when building from repository.
diff --git a/nt/gnulib.mk b/nt/gnulib.mk
index 7877c154b96..7c2cceb959f 100644
--- a/nt/gnulib.mk
+++ b/nt/gnulib.mk
@@ -671,57 +671,6 @@ EXTRA_DIST += stdalign.in.h
 
 ## end   gnulib module stdalign
 
-## begin gnulib module stdarg
-
-BUILT_SOURCES += $(STDARG_H)
-
-# We need the following in order to create <stdarg.h> when the system
-# doesn't have one that works with the given compiler.
-if GL_GENERATE_STDARG_H
-stdarg.h: stdarg.in.h $(top_builddir)/config.status
-        $(AM_V_GEN)rm -f $@-t $@ && \
-        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */' && \
-          sed -e 's|@''GUARD_PREFIX''@|GL|g' \
-              -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
-              -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
-              -e 's|@''PRAGMA_COLUMNS''@|@PRAGMA_COLUMNS@|g' \
-              -e 's|@''NEXT_STDARG_H''@|$(NEXT_STDARG_H)|g' \
-              < $(srcdir)/stdarg.in.h; \
-        } > $@-t && \
-        mv $@-t $@
-else
-stdarg.h: $(top_builddir)/config.status
-        rm -f $@
-endif
-MOSTLYCLEANFILES += stdarg.h stdarg.h-t
-
-EXTRA_DIST += stdarg.in.h
-
-## end   gnulib module stdarg
-
-## begin gnulib module stdbool
-
-BUILT_SOURCES += $(STDBOOL_H)
-
-# We need the following in order to create <stdbool.h> when the system
-# doesn't have one that works.
-if GL_GENERATE_STDBOOL_H
-stdbool.h: stdbool.in.h $(top_builddir)/config.status
-        $(AM_V_GEN)rm -f $@-t $@ && \
-        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
-          sed -e 's/@''HAVE__BOOL''@/$(HAVE__BOOL)/g' < $(srcdir)/stdbool.in.h; \
-        } > $@-t && \
-        mv $@-t $@
-else
-stdbool.h: $(top_builddir)/config.status
-        rm -f $@
-endif
-MOSTLYCLEANFILES += stdbool.h stdbool.h-t
-
-EXTRA_DIST += stdbool.in.h
-
-## end   gnulib module stdbool
-
 ## begin gnulib module stddef
 
 BUILT_SOURCES += $(STDDEF_H)
diff --git a/src/ChangeLog b/src/ChangeLog
index a89d14bbe23..31fe13e074c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,13 @@
+2014-05-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Assume C99 or later (Bug#17487).
+        * bytecode.c (B__dummy__): Remove.
+        * conf_post.h (bool_bf) [!NS_IMPL_GNUSTEP]: Use bool.
+        (FLEXIBLE_ARRAY_MEMBER): Now always empty.
+        * dbusbind.c (XD_DEBUG_MESSAGE) [!DBUS_DEBUG]:
+        * regex.c (DEBUG_PRINT): Assume varargs macros.
+        * lisp.h (DEFUN_FUNCTION_INIT): Remove.  All uses now assume C99.
+
 2014-05-17  Fabrice Popineau  <fabrice.popineau@gmail.com>
 
         * buffer.c (init_buffer) [USE_MMAP_FOR_BUFFERS]: Always map new
diff --git a/src/bytecode.c b/src/bytecode.c
index f1bdfd9d9c5..f489c74a144 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -292,8 +292,6 @@ enum byte_code_op
     Bscan_buffer = 0153, /* No longer generated as of v18.  */
     Bset_mark = 0163, /* this loser is no longer generated as of v18 */
 #endif
-
-    B__dummy__ = 0  /* Pacify C89.  */
 };
 
 /* Whether to maintain a `top' and `bottom' field in the stack frame.  */
diff --git a/src/conf_post.h b/src/conf_post.h
index 95b028a66ee..123f4803da5 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -34,9 +34,10 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <stdbool.h>
 
-/* The pre-C99 <stdbool.h> emulation doesn't work for bool bitfields.
-   Nor does compiling Objective-C with standard GCC.  */
-#if __STDC_VERSION__ < 199901 || NS_IMPL_GNUSTEP
+/* The type of bool bitfields.  Needed to compile Objective-C with
+   standard GCC.  It was also needed to port to pre-C99 compilers,
+   although we don't care about that any more.  */
+#if NS_IMPL_GNUSTEP
 typedef unsigned int bool_bf;
 #else
 typedef bool bool_bf;
@@ -293,14 +294,11 @@ extern void _DebPrint (const char *fmt, ...);
 
 /* To use the struct hack with N elements, declare the struct like this:
      struct s { ...; t name[FLEXIBLE_ARRAY_MEMBER]; };
-   and allocate (offsetof (struct s, name) + N * sizeof (t)) bytes.  */
-#if 199901 <= __STDC_VERSION__
-# define FLEXIBLE_ARRAY_MEMBER
-#elif __GNUC__ && !defined __STRICT_ANSI__
-# define FLEXIBLE_ARRAY_MEMBER 0
-#else
-# define FLEXIBLE_ARRAY_MEMBER 1
-#endif
+   and allocate (offsetof (struct s, name) + N * sizeof (t)) bytes.
+
+   This macro used to expand to something different on pre-C99 compilers.
+   FIXME: Remove it, and remove all uses.  */
+#define FLEXIBLE_ARRAY_MEMBER
 
 /* Use this to suppress gcc's `...may be used before initialized' warnings. */
 #ifdef lint
diff --git a/src/dbusbind.c b/src/dbusbind.c
index 8ebc56c72c4..8997e01b068 100644
--- a/src/dbusbind.c
+++ b/src/dbusbind.c
@@ -142,10 +142,7 @@ static bool xd_in_read_queued_messages = 0;
   } while (0)
 
 #else /* !DBUS_DEBUG */
-# if __STDC_VERSION__ < 199901
-#  define XD_DEBUG_MESSAGE (void) /* Pre-C99 compilers cannot debug.  */
-# else
-#  define XD_DEBUG_MESSAGE(...)                                         \
+# define XD_DEBUG_MESSAGE(...)                                          \
   do {                                                                  \
     if (!NILP (Vdbus_debug))                                            \
       {                                                                 \
@@ -154,7 +151,6 @@ static bool xd_in_read_queued_messages = 0;
         message ("%s: %s", __func__, s);                                \
       }                                                                 \
   } while (0)
-# endif
 # define XD_DEBUG_VALID_LISP_OBJECT_P(object)
 #endif
 
diff --git a/src/emacs.c b/src/emacs.c
index deebb2280c7..16d91de84a4 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -214,7 +214,7 @@ int initial_argc;
 static void sort_args (int argc, char **argv);
 static void syms_of_emacs (void);
 
-/* C89 needs each string be at most 509 characters, so the usage
+/* C99 needs each string to be at most 4095 characters, and the usage
    strings below are split to not overflow this limit.  */
 static char const *const usage_message[] =
   { "\
diff --git a/src/lisp.h b/src/lisp.h
index f47fb0c2a24..67b26ef91c7 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2654,16 +2654,11 @@ CHECK_NUMBER_CDR (Lisp_Object x)
        minargs, maxargs, lname, intspec, 0};                            \
    Lisp_Object fnname
 #else  /* not _MSC_VER */
-# if __STDC_VERSION__ < 199901
-#  define DEFUN_FUNCTION_INIT(fnname, maxargs) (Lisp_Object (*) (void)) fnname
-# else
-#  define DEFUN_FUNCTION_INIT(fnname, maxargs) .a ## maxargs = fnname
-# endif
 #define DEFUN(lname, fnname, sname, minargs, maxargs, intspec, doc)     \
    Lisp_Object fnname DEFUN_ARGS_ ## maxargs ;                          \
    static struct Lisp_Subr alignas (GCALIGNMENT) sname =                \
      { { PVEC_SUBR << PSEUDOVECTOR_AREA_BITS },                         \
-       { DEFUN_FUNCTION_INIT (fnname, maxargs) },                       \
+       { .a ## maxargs = fnname },                                      \
        minargs, maxargs, lname, intspec, 0};                            \
    Lisp_Object fnname
 #endif
diff --git a/src/regex.c b/src/regex.c
index 622db708b98..ac71b797fbd 100644
--- a/src/regex.c
+++ b/src/regex.c
@@ -1190,12 +1190,7 @@ print_double_string (re_char *where, re_char *string1, ssize_t size1,
 # define assert(e)
 
 # define DEBUG_STATEMENT(e)
-# if __STDC_VERSION__ < 199901L
-#  define DEBUG_COMPILES_ARGUMENTS
-#  define DEBUG_PRINT /* 'DEBUG_PRINT (x, y)' discards X and Y.  */ (void)
-# else
-#  define DEBUG_PRINT(...)
-# endif
+# define DEBUG_PRINT(...)
 # define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)
 # define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)