Substitute a <ieee754.h> on hosts lacking it

* .gitignore: Add lib/ieee754.h.
* admin/merge-gnulib (GNULIB_MODULES): Add ieee754-h.
* configure.ac: Remove ieee754.h check, as Gnulib now does that.
* etc/NEWS: Mention this.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/ieee754.in.h, m4/ieee754-h.m4: New files, from Gnulib.
* src/lisp.h (IEEE_FLOATING_POINT): Now a macro so that it
can be used in #if.
* src/lread.c, src/print.c: Include <ieee754.h> if
IEEE_FLOATING_POINT, not if HAVE_IEEE754_H.
* src/lread.c (string_to_number):
* src/print.c (float_to_string):
Process NaNs only on IEEE hosts, and assume <ieee754.h>
in that case.

2 files changed, 25 insertions, 0 deletions

diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index a6e3be3815d..494c77c7c4e 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -101,6 +101,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module gettimeofday:
   # Code from module gitlog-to-changelog:
   # Code from module group-member:
+  # Code from module ieee754-h:
   # Code from module ignore-value:
   # Code from module include_next:
   # Code from module intprops:
@@ -295,6 +296,7 @@ AC_DEFUN([gl_INIT],
     gl_PREREQ_GETTIMEOFDAY
   fi
   gl_SYS_TIME_MODULE_INDICATOR([gettimeofday])
+  gl_IEEE754_H
   gl_INTTYPES_INCOMPLETE
   AC_REQUIRE([gl_LARGEFILE])
   gl_LIMITS_H
@@ -895,6 +897,7 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/gettimeofday.c
   lib/gl_openssl.h
   lib/group-member.c
+  lib/ieee754.in.h
   lib/ignore-value.h
   lib/intprops.h
   lib/inttypes.in.h
@@ -1017,6 +1020,7 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/gl-openssl.m4
   m4/gnulib-common.m4
   m4/group-member.m4
+  m4/ieee754-h.m4
   m4/include_next.m4
   m4/inttypes.m4
   m4/largefile.m4
diff --git a/m4/ieee754-h.m4 b/m4/ieee754-h.m4
new file mode 100644
index 00000000000..bf7c332e48e
--- /dev/null
+++ b/m4/ieee754-h.m4
@@ -0,0 +1,21 @@
+# Configure ieee754-h module
+
+dnl Copyright 2018 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.
+
+AC_DEFUN([gl_IEEE754_H],
+[
+  AC_REQUIRE([AC_C_BIGENDIAN])
+  AC_CHECK_HEADERS_ONCE([ieee754.h])
+  if test $ac_cv_header_ieee754_h = yes; then
+    IEEE754_H=
+  else
+    IEEE754_H=ieee754.h
+    AC_DEFINE([_GL_REPLACE_IEEE754_H], 1,
+              [Define to 1 if <ieee754.h> is missing.])
+  fi
+  AC_SUBST([IEEE754_H])
+  AM_CONDITIONAL([GL_GENERATE_IEEE754_H], [test -n "$IEEE754_H"])
+])