check INFINITY and NAN without C99 option

* configure.in: check INFINITY and NAN without an option for C99
  so that rb_infinity and rb_nan are respectively available
  regardless that option if they may be used.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52197 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.in

@@ -839,6 +839,20 @@ if test "$GCC:${warnflags+set}:no" = yes::no; then
 fi
 RUBY_TRY_CFLAGS(-Qunused-arguments, [RUBY_APPEND_OPTIONS(rb_cv_wsuppress_flags, -Qunused-arguments)])
 
+for n in infinity nan; do
+    m=AS_TR_CPP($n)
+    AC_CACHE_CHECK([whether $m is available without C99 option], rb_cv_$n,
+	[AC_COMPILE_IFELSE(
+	    [AC_LANG_BOOL_COMPILE_TRY(AC_INCLUDES_DEFAULT([@%:@include <math.h>
+@%:@ifndef $m
+@%:@error no $m
+@%:@endif
+]), [1])], [eval rb_cv_$n=yes], [eval rb_cv_$n=no])])
+    if eval test '"$rb_cv_'$n'"' = yes; then
+	AC_DEFINE_UNQUOTED([HAVE_]$m)
+    fi
+done
+
 if test "$GCC" = yes; then
     # NaCl's glibc build generates undefined references to __memset_chk.
     # TODO(sbc): Remove this once NaCl's glibc is fixed.

ext/date/extconf.rb

@@ -1,3 +1,2 @@
 require 'mkmf'
-append_cflags("-std=iso9899:1999")
 create_makefile('date_core')

include/ruby/missing.h

@@ -143,17 +143,13 @@ union bytesequence4_or_float {
 };
 #endif
 
-#ifdef INFINITY
-# define HAVE_INFINITY
-#else
+#ifndef INFINITY
 /** @internal */
 RUBY_EXTERN const union bytesequence4_or_float rb_infinity;
 # define INFINITY (rb_infinity.float_value)
 #endif
 
-#ifdef NAN
-# define HAVE_NAN
-#else
+#ifndef NAN
 /** @internal */
 RUBY_EXTERN const union bytesequence4_or_float rb_nan;
 # define NAN (rb_nan.float_value)