Mesa (glsl2): mesa: Check that _XOPEN_SOURCE is defined before using it.

[Vinson Lee]

Module: Mesa
Branch: glsl2
Commit: a0b0afc6944b00df27145a96ad2727a36752e1d6
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=a0b0afc6944b00df27145a96ad2727a36752e1d6

Author: Vinson Lee <vlee at vmware.com>
Date:   Sun Aug 15 13:08:15 2010 -0700

mesa: Check that _XOPEN_SOURCE is defined before using it.

---

 src/mesa/main/imports.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/mesa/main/imports.h b/src/mesa/main/imports.h
index a439370..e967b14 100644
--- a/src/mesa/main/imports.h
+++ b/src/mesa/main/imports.h
@@ -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))