Removed GLFW 2 option macro.

GLFW_NO_GLU is a GLFW 2 feature. GLFW 3 does not include the GLU header by default.
11 years ago · 57308993cb
--- a/example/example_gl3.c
+++ b/example/example_gl3.c
@@ -20,7 +20,6 @@
 #ifdef NANOVG_GLEW
 #	include <GL/glew.h>
 #endif
 #define GLFW_NO_GLU
 #ifdef __APPLE__
 #	define GLFW_INCLUDE_GLCOREARB
 #endif