mesa: Check that _XOPEN_SOURCE is defined before using it.

2010-08-15 13:08:15 -07:00
parent 9349379d1a
commit a0b0afc694
1 changed files with 1 additions and 1 deletions
@@ -120,7 +120,7 @@ typedef union { GLfloat f; GLint i; } fi_type;
 * \name Work-arounds for platforms that lack C99 math functions
 */
 /*@{*/
-#if (_XOPEN_SOURCE < 600) && !defined(_ISOC99_SOURCE) \
+#if (defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE < 600)) && !defined(_ISOC99_SOURCE) \
   && (!defined(__STDC_VERSION__) || (__STDC_VERSION__ < 199901L)) \
   && (!defined(_MSC_VER) || (_MSC_VER < 1400))
 #define acosf(f) ((float) acos(f))