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.

1 files changed, 222 insertions, 0 deletions

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 */