Fixed OpenGL configure: move HAVE_OPENGL define to where it belongs,
fixed glext.h presence in configure check for PFNGLCOLORTABLEEXTPROC.

diff --git a/configure.in b/configure.in
index d296f42..7ae4d84 100644
--- a/configure.in
+++ b/configure.in
@@ -268,6 +268,7 @@
 
 
 		OPENGLFILES='$(OPENGLFILES)'
+		AC_DEFINE(HAVE_OPENGL)
 
 		if test $ac_cv_lib_GL_glXCreateContext = "yes"
 		then
@@ -277,7 +278,10 @@
 			then
 			       AC_CACHE_CHECK("for OpenGL extension functions prototypes", wine_cv_extension_prototypes,
 			          AC_TRY_COMPILE([#include <GL/gl.h>
-						  #include <GL/glext.h>],
+				  		  #ifdef HAVE_GL_GLEXT_H
+						  # include <GL/glext.h>
+						  #endif
+						  ],
 						 [PFNGLCOLORTABLEEXTPROC test_proc;],
 						 [wine_cv_extension_prototypes="yes"],
 						 [wine_cv_extension_prototypes="no"]
@@ -288,7 +292,6 @@
 					AC_DEFINE(HAVE_GLEXT_PROTOTYPES)
 				fi
 
-				AC_DEFINE(HAVE_OPENGL)
 				OPENGL32_DLL=opengl32
 			fi
 		fi