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, 251 insertions, 0 deletions

diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index e623921091f..7d28dcc62b8 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -95,6 +95,7 @@
 #  gettime \
 #  gettimeofday \
 #  gitlog-to-changelog \
+#  ieee754-h \
 #  ignore-value \
 #  intprops \
 #  largefile \
@@ -220,6 +221,7 @@ GL_GENERATE_ALLOCA_H = @GL_GENERATE_ALLOCA_H@
 GL_GENERATE_BYTESWAP_H = @GL_GENERATE_BYTESWAP_H@
 GL_GENERATE_ERRNO_H = @GL_GENERATE_ERRNO_H@
 GL_GENERATE_EXECINFO_H = @GL_GENERATE_EXECINFO_H@
+GL_GENERATE_IEEE754_H = @GL_GENERATE_IEEE754_H@
 GL_GENERATE_LIMITS_H = @GL_GENERATE_LIMITS_H@
 GL_GENERATE_STDALIGN_H = @GL_GENERATE_STDALIGN_H@
 GL_GENERATE_STDDEF_H = @GL_GENERATE_STDDEF_H@
@@ -646,6 +648,7 @@ HAVE_WINSOCK2_H = @HAVE_WINSOCK2_H@
 HAVE_XSERVER = @HAVE_XSERVER@
 HAVE__EXIT = @HAVE__EXIT@
 HYBRID_MALLOC = @HYBRID_MALLOC@
+IEEE754_H = @IEEE754_H@
 IMAGEMAGICK_CFLAGS = @IMAGEMAGICK_CFLAGS@
 IMAGEMAGICK_LIBS = @IMAGEMAGICK_LIBS@
 INCLUDE_NEXT = @INCLUDE_NEXT@
@@ -1787,6 +1790,32 @@ EXTRA_libgnu_a_SOURCES += group-member.c
 endif
 ## end   gnulib module group-member
 
+## begin gnulib module ieee754-h
+ifeq (,$(OMIT_GNULIB_MODULE_ieee754-h))
+
+BUILT_SOURCES += $(IEEE754_H)
+
+# We need the following in order to create <ieee754.h> when the system
+# doesn't have one that works with the given compiler.
+ifneq (,$(GL_GENERATE_IEEE754_H))
+ieee754.h: ieee754.in.h $(top_builddir)/config.status
+        $(AM_V_GEN)rm -f $@-t && \
+        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
+          sed -e 's/ifndef _GL_GNULIB_HEADER/if 0/g' \
+            $(srcdir)/ieee754.in.h; \
+        } > $@-t && \
+        mv -f $@-t $@
+else
+ieee754.h: $(top_builddir)/config.status
+        rm -f $@
+endif
+MOSTLYCLEANFILES += ieee754.h ieee754.h-t
+
+EXTRA_DIST += ieee754.in.h
+
+endif
+## end   gnulib module ieee754-h
+
 ## begin gnulib module ignore-value
 ifeq (,$(OMIT_GNULIB_MODULE_ignore-value))
 
diff --git a/lib/ieee754.in.h b/lib/ieee754.in.h
new file mode 100644
index 00000000000..316ac039afe
--- /dev/null
+++ b/lib/ieee754.in.h
@@ -0,0 +1,222 @@
+/* Copyright (C) 1992-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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 of the License, or (at your option) any later version.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _IEEE754_H
+
+#define _IEEE754_H 1
+
+#ifndef _GL_GNULIB_HEADER
+/* Ordinary glibc usage.  */
+# include <features.h>
+# include <endian.h>
+#else
+/* Gnulib usage.  */
+# ifndef __BEGIN_DECLS
+#  ifdef __cplusplus
+#   define __BEGIN_DECLS        extern "C" {
+#   define __END_DECLS          }
+#  else
+#   define __BEGIN_DECLS
+#   define __END_DECLS
+#  endif
+# endif
+# ifndef __FLOAT_WORD_ORDER
+#  define __LITTLE_ENDIAN       1234
+#  define __BIG_ENDIAN          4321
+#  ifdef WORDS_BIGENDIAN
+#   define __BYTE_ORDER __BIG_ENDIAN
+#  else
+#   define __BYTE_ORDER __LITTLE_ENDIAN
+#  endif
+#  define __FLOAT_WORD_ORDER __BYTE_ORDER
+# endif
+#endif
+
+__BEGIN_DECLS
+
+union ieee754_float
+  {
+    float f;
+
+    /* This is the IEEE 754 single-precision format.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:8;
+        unsigned int mantissa:23;
+#endif                          /* Big endian.  */
+#if     __BYTE_ORDER == __LITTLE_ENDIAN
+        unsigned int mantissa:23;
+        unsigned int exponent:8;
+        unsigned int negative:1;
+#endif                          /* Little endian.  */
+      } ieee;
+
+    /* This format makes it easier to see if a NaN is a signalling NaN.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:8;
+        unsigned int quiet_nan:1;
+        unsigned int mantissa:22;
+#endif                          /* Big endian.  */
+#if     __BYTE_ORDER == __LITTLE_ENDIAN
+        unsigned int mantissa:22;
+        unsigned int quiet_nan:1;
+        unsigned int exponent:8;
+        unsigned int negative:1;
+#endif                          /* Little endian.  */
+      } ieee_nan;
+  };
+
+#define IEEE754_FLOAT_BIAS      0x7f /* Added to exponent.  */
+
+
+union ieee754_double
+  {
+    double d;
+
+    /* This is the IEEE 754 double-precision format.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:11;
+        /* Together these comprise the mantissa.  */
+        unsigned int mantissa0:20;
+        unsigned int mantissa1:32;
+#endif                          /* Big endian.  */
+#if     __BYTE_ORDER == __LITTLE_ENDIAN
+# if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
+        unsigned int mantissa0:20;
+        unsigned int exponent:11;
+        unsigned int negative:1;
+        unsigned int mantissa1:32;
+# else
+        /* Together these comprise the mantissa.  */
+        unsigned int mantissa1:32;
+        unsigned int mantissa0:20;
+        unsigned int exponent:11;
+        unsigned int negative:1;
+# endif
+#endif                          /* Little endian.  */
+      } ieee;
+
+    /* This format makes it easier to see if a NaN is a signalling NaN.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:11;
+        unsigned int quiet_nan:1;
+        /* Together these comprise the mantissa.  */
+        unsigned int mantissa0:19;
+        unsigned int mantissa1:32;
+#else
+# if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
+        unsigned int mantissa0:19;
+        unsigned int quiet_nan:1;
+        unsigned int exponent:11;
+        unsigned int negative:1;
+        unsigned int mantissa1:32;
+# else
+        /* Together these comprise the mantissa.  */
+        unsigned int mantissa1:32;
+        unsigned int mantissa0:19;
+        unsigned int quiet_nan:1;
+        unsigned int exponent:11;
+        unsigned int negative:1;
+# endif
+#endif
+      } ieee_nan;
+  };
+
+#define IEEE754_DOUBLE_BIAS     0x3ff /* Added to exponent.  */
+
+
+union ieee854_long_double
+  {
+    long double d;
+
+    /* This is the IEEE 854 double-extended-precision format.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:15;
+        unsigned int empty:16;
+        unsigned int mantissa0:32;
+        unsigned int mantissa1:32;
+#endif
+#if     __BYTE_ORDER == __LITTLE_ENDIAN
+# if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
+        unsigned int exponent:15;
+        unsigned int negative:1;
+        unsigned int empty:16;
+        unsigned int mantissa0:32;
+        unsigned int mantissa1:32;
+# else
+        unsigned int mantissa1:32;
+        unsigned int mantissa0:32;
+        unsigned int exponent:15;
+        unsigned int negative:1;
+        unsigned int empty:16;
+# endif
+#endif
+      } ieee;
+
+    /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
+    struct
+      {
+#if     __BYTE_ORDER == __BIG_ENDIAN
+        unsigned int negative:1;
+        unsigned int exponent:15;
+        unsigned int empty:16;
+        unsigned int one:1;
+        unsigned int quiet_nan:1;
+        unsigned int mantissa0:30;
+        unsigned int mantissa1:32;
+#endif
+#if     __BYTE_ORDER == __LITTLE_ENDIAN
+# if    __FLOAT_WORD_ORDER == __BIG_ENDIAN
+        unsigned int exponent:15;
+        unsigned int negative:1;
+        unsigned int empty:16;
+        unsigned int mantissa0:30;
+        unsigned int quiet_nan:1;
+        unsigned int one:1;
+        unsigned int mantissa1:32;
+# else
+        unsigned int mantissa1:32;
+        unsigned int mantissa0:30;
+        unsigned int quiet_nan:1;
+        unsigned int one:1;
+        unsigned int exponent:15;
+        unsigned int negative:1;
+        unsigned int empty:16;
+# endif
+#endif
+      } ieee_nan;
+  };
+
+#define IEEE854_LONG_DOUBLE_BIAS 0x3fff
+
+__END_DECLS
+
+#endif /* ieee754.h */