From a136734f3fdc17bfb5924e30e597b00057c916d0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 7 Mar 2017 09:50:15 -0800
Subject: [PATCH] Remove isnan hack for Solaris 10 gcc 3.4.3

This seems to have been a false alarm (Bug#26018).
* src/data.c (isnan):
* src/floatfns.c (isfinite, isnan):
Use standard implementation if available.
---
 src/data.c     |  7 +++++--
 src/floatfns.c | 13 ++++++-------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/data.c b/src/data.c
index ae88e3f8aa5..29547d8a9ba 100644
--- a/src/data.c
+++ b/src/data.c
@@ -19,6 +19,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 
 #include <config.h>
+
+#include <math.h>
 #include <stdio.h>
 
 #include <byteswap.h>
@@ -2812,8 +2814,9 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args)
   return val;
 }
 
-#undef isnan
-#define isnan(x) ((x) != (x))
+#ifndef isnan
+# define isnan(x) ((x) != (x))
+#endif
 
 static Lisp_Object
 float_arith_driver (double accum, ptrdiff_t argnum, enum arithop code,
diff --git a/src/floatfns.c b/src/floatfns.c
index 8534f1d04e4..47553f27e82 100644
--- a/src/floatfns.c
+++ b/src/floatfns.c
@@ -47,13 +47,12 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <count-leading-zeros.h>
 
-/* 'isfinite' and 'isnan' cause build failures on Solaris 10 with the
-   bundled GCC in c99 mode.  Work around the bugs with simple
-   implementations that are good enough.  */
-#undef isfinite
-#define isfinite(x) ((x) - (x) == 0)
-#undef isnan
-#define isnan(x) ((x) != (x))
+#ifndef isfinite
+# define isfinite(x) ((x) - (x) == 0)
+#endif
+#ifndef isnan
+# define isnan(x) ((x) != (x))
+#endif
 
 /* Check that X is a floating point number.  */
 
-- 
2.39.5