Move __STDC_CONSTANT_MACROS/__STDC_LIMIT_MACROS defs earlier

These defines should apply to windows as well,
so move them out of the non-windows specific section
and always define them for C++ compilations.

main/php_stdint.h

@@ -19,6 +19,25 @@
 #ifndef PHP_STDINT_H
 #define PHP_STDINT_H
 
+/* C99 requires these for C++ to get the definitions
+ * of INT64_MAX and other macros used by Zend/zend_long.h
+ * C11 drops this requirement, so these effectively
+ * just backport that piece of behavior.
+ *
+ * These defines are placed here instead of
+ * with the include below, because sys/types
+ * and inttypes may include stdint themselves.
+ * And these definitions MUST come first.
+ */
+#ifdef __cplusplus
+# ifndef __STDC_LIMIT_MACROS
+#  define __STDC_LIMIT_MACROS
+# endif
+# ifndef __STDC_CONSTANT_MACROS
+#  define __STDC_CONSTANT_MACROS
+# endif
+#endif
+
 #if defined(_MSC_VER)
 /* Make sure the regular stdint.h wasn't included already and prevent it to be
    included afterwards. Though if some other library needs some stuff from
@@ -42,21 +61,6 @@
 
 #include "php_config.h"
 
-#if HAVE_STDINT_H && defined(__cplusplus)
-  /* C99 requires these for C++ to get the definitions
-   * of INT64_MAX and other macros used by Zend/zend_long.h
-   * C11 drops this requirement, so these effectively
-   * just backport that piece of behavior.
-   *
-   * These defines are placed here instead of
-   * with the include below, because sys/types
-   * and inttypes may include stdint themselves.
-   * And these definitions MUST come first.
-   */
-# define __STDC_LIMIT_MACROS
-# define __STDC_CONSTANT_MACROS
-#endif
-
 #if HAVE_SYS_TYPES_H
 # include <sys/types.h>
 #endif