Enable isinf/isnan checks for all targets

	PR libstdc++/48891
	* acinclude.m4 (GLIBCXX_CHECK_MATH11_PROTO): Enable isinf and isnan
	checks for all targets except *-*-solaris2.* and ensure we find the
	libc math.h header not our own.
	* configure: Regenerate.

From-SVN: r233214

libstdc++-v3/ChangeLog

+2016-02-08  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/48891
+	* acinclude.m4 (GLIBCXX_CHECK_MATH11_PROTO): Enable isinf and isnan
+	checks for all targets except *-*-solaris2.* and ensure we find the
+	libc math.h header not our own.
+	* configure: Regenerate.
+
 2016-02-05  Dominik Vogt  <vogt@linux.vnet.ibm.com>
 
 	* config/abi/post/s390x-linux-gnu/32/baseline_symbols.txt (FUNC):

libstdc++-v3/acinclude.m4

@@ -2215,7 +2215,7 @@ AC_DEFUN([GLIBCXX_CHECK_MATH11_PROTO], [
       fi
       AC_MSG_RESULT([$glibcxx_cv_math11_overload])
       ;;
-    *-*-*gnu* | *-*-aix* | *-*-hpux*)
+    *)
       # If <math.h> defines the obsolete isinf(double) and isnan(double)
       # functions (instead of or as well as the C99 generic macros) then we
       # can't define std::isinf(double) and std::isnan(double) in <cmath>
@@ -2223,12 +2223,13 @@ AC_DEFUN([GLIBCXX_CHECK_MATH11_PROTO], [
       AC_MSG_CHECKING([for obsolete isinf function in <math.h>])
         AC_CACHE_VAL(glibcxx_cv_obsolete_isinf, [
           AC_COMPILE_IFELSE([AC_LANG_SOURCE(
-            [#include <math.h>
+            [#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+             #include <math.h>
              #undef isinf
              namespace std {
                using ::isinf;
-               bool isinf(float);
-               bool isinf(long double);
+               constexpr bool isinf(float);
+               constexpr bool isinf(long double);
              }
              using std::isinf;
              bool b = isinf(0.0);

libstdc++-v3/configure

@@ -18266,7 +18266,7 @@ fi
       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $glibcxx_cv_math11_overload" >&5
 $as_echo "$glibcxx_cv_math11_overload" >&6; }
       ;;
-    *-*-*gnu* | *-*-aix* | *-*-hpux*)
+    *)
       # If <math.h> defines the obsolete isinf(double) and isnan(double)
       # functions (instead of or as well as the C99 generic macros) then we
       # can't define std::isinf(double) and std::isnan(double) in <cmath>
@@ -18279,12 +18279,13 @@ else
 
           cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <math.h>
+#define _GLIBCXX_INCLUDE_NEXT_C_HEADERS
+             #include <math.h>
              #undef isinf
              namespace std {
                using ::isinf;
-               bool isinf(float);
-               bool isinf(long double);
+               constexpr bool isinf(float);
+               constexpr bool isinf(long double);
              }
              using std::isinf;
              bool b = isinf(0.0);