diff --git a/Zend/configure.ac b/Zend/configure.ac
index 694ecbc8888..8252cfb3426 100644
--- a/Zend/configure.ac
+++ b/Zend/configure.ac
@@ -50,16 +50,10 @@ int zend_sprintf(char *buffer, const char *format, ...);
 # define zend_sprintf sprintf
 #endif
 
-#if defined(__cplusplus) && __cplusplus >= 201103L
-#include <cmath>
-#define zend_isnan std::isnan
-#define zend_isinf std::isinf
-#define zend_finite std::isfinite
-#else
 #include <math.h>
 
 #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))
@@ -68,7 +62,7 @@ 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 */
@@ -79,7 +73,7 @@ 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)
@@ -89,8 +83,6 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #define zend_finite(a) (zend_isnan(a) ? 0 : zend_isinf(a) ? 0 : 1)
 #endif
 
-#endif
-
 #endif /* ifndef ZEND_ACCONFIG_H_NO_C_PROTOS */
 
 ])
diff --git a/Zend/zend_config.w32.h b/Zend/zend_config.w32.h
index 37442ff018e..71d550e57ba 100644
--- a/Zend/zend_config.w32.h
+++ b/Zend/zend_config.w32.h
@@ -50,16 +50,9 @@ typedef unsigned int uint;
 #endif
 #define strcasecmp(s1, s2) _stricmp(s1, s2)
 #define strncasecmp(s1, s2, n) _strnicmp(s1, s2, n)
-#if defined(__cplusplus) && __cplusplus >= 201103L
-#include <cmath>
-#define zend_isnan std::isnan
-#define zend_isinf std::isinf
-#define zend_finite std::isfinite
-#else
 #define zend_isinf(a)	((_fpclass(a) == _FPCLASS_PINF) || (_fpclass(a) == _FPCLASS_NINF))
 #define zend_finite(x)	_finite(x)
 #define zend_isnan(x)	_isnan(x)
-#endif
 
 #define zend_sprintf sprintf
 
diff --git a/configure.ac b/configure.ac
index bd9a065ce12..09cb2706bbc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -59,16 +59,10 @@ int zend_sprintf(char *buffer, const char *format, ...);
 # define zend_sprintf sprintf
 #endif
 
-#if defined(__cplusplus) && __cplusplus >= 201103L
-#include <cmath>
-#define zend_isnan std::isnan
-#define zend_isinf std::isinf
-#define zend_finite std::isfinite
-#else
 #include <math.h>
 
 #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))
@@ -77,7 +71,7 @@ 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 */
@@ -88,7 +82,7 @@ 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)
@@ -98,7 +92,6 @@ int zend_sprintf(char *buffer, const char *format, ...);
 #define zend_finite(a) (zend_isnan(a) ? 0 : zend_isinf(a) ? 0 : 1)
 #endif
 
-#endif
 #endif /* ifndef ZEND_ACCONFIG_H_NO_C_PROTOS */
 
 #undef PTHREADS