Be more consistant with paths in #includes.  Eventually, eliminate a bunch of -I flags.
diff --git a/src/mesa/math/m_eval.h b/src/mesa/math/m_eval.h
index a23cbd4..d73ecaa 100644
--- a/src/mesa/math/m_eval.h
+++ b/src/mesa/math/m_eval.h
@@ -26,7 +26,7 @@
 #ifndef _M_EVAL_H
 #define _M_EVAL_H
 
-#include "glheader.h"
+#include "main/glheader.h"
 
 void _math_init_eval( void );