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, 4 insertions, 7 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 96de60e4670..bdece817bd6 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2670,17 +2670,14 @@ XFLOAT_DATA (Lisp_Object f)
 
 /* Most hosts nowadays use IEEE floating point, so they use IEC 60559
    representations, have infinities and NaNs, and do not trap on
-   exceptions.  Define IEEE_FLOATING_POINT if this host is one of the
+   exceptions.  Define IEEE_FLOATING_POINT to 1 if this host is one of the
    typical ones.  The C11 macro __STDC_IEC_559__ is close to what is
    wanted here, but is not quite right because Emacs does not require
    all the features of C11 Annex F (and does not require C11 at all,
    for that matter).  */
-enum
-  {
-    IEEE_FLOATING_POINT
-      = (FLT_RADIX == 2 && FLT_MANT_DIG == 24
-         && FLT_MIN_EXP == -125 && FLT_MAX_EXP == 128)
-  };
+
+#define IEEE_FLOATING_POINT (FLT_RADIX == 2 && FLT_MANT_DIG == 24 \
+                             && FLT_MIN_EXP == -125 && FLT_MAX_EXP == 128)
 
 /* A character, declared with the following typedef, is a member
    of some character set associated with the current buffer.  */