Fix C++11 and up compatibility for zend_finite and more

C++11 puts isfinite, isinf, isnan and a lot of other stuff into the
std namespace. Thus, if a C++11 or newer source is compiled, these
symbols won't be available. A good solution would be to include cmath,
but depending on a particular compiler that might remove even more
stuff from the global namespace, so such a fix should only target master.
For now, just keep these defines same for C++11 and upper, as the actual
C++ code should use symbols from the std namespace anyway. This
especially concerns older GCC versions like at least 4 and 5, which are
used by default in the LTS Linux distros.

Author: weltling

Zend/configure.in

@@ -70,7 +70,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #endif
 
 #ifndef zend_isnan
-#if HAVE_DECL_ISNAN
+#if HAVE_DECL_ISNAN && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_isnan(a) isnan(a)
 #elif defined(HAVE_FPCLASS)
 #define zend_isnan(a) ((fpclass(a) == FP_SNAN) || (fpclass(a) == FP_QNAN))
@@ -79,7 +79,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #endif
 #endif
 
-#if HAVE_DECL_ISINF
+#if HAVE_DECL_ISINF && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_isinf(a) isinf(a)
 #elif defined(INFINITY)
 /* Might not work, but is required by ISO C99 */
@@ -90,7 +90,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #define zend_isinf(a) 0
 #endif
 
-#if HAVE_DECL_ISFINITE
+#if HAVE_DECL_ISFINITE && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_finite(a) isfinite(a)
 #elif defined(HAVE_FINITE)
 #define zend_finite(a) finite(a)

configure.in

@@ -75,7 +75,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #endif
 
 #ifndef zend_isnan
-#if HAVE_DECL_ISNAN
+#if HAVE_DECL_ISNAN && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_isnan(a) isnan(a)
 #elif defined(HAVE_FPCLASS)
 #define zend_isnan(a) ((fpclass(a) == FP_SNAN) || (fpclass(a) == FP_QNAN))
@@ -84,7 +84,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #endif
 #endif
 
-#if HAVE_DECL_ISINF
+#if HAVE_DECL_ISINF && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_isinf(a) isinf(a)
 #elif defined(INFINITY)
 /* Might not work, but is required by ISO C99 */
@@ -95,7 +95,7 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #define zend_isinf(a) 0
 #endif
 
-#if HAVE_DECL_ISFINITE
+#if HAVE_DECL_ISFINITE && (!defined(__cplusplus) || __cplusplus < 201103L)
 #define zend_finite(a) isfinite(a)
 #elif defined(HAVE_FINITE)
 #define zend_finite(a) finite(a)