Reduce the difference of glfw to upstream

This only changes some formatting, whitespace, etc.. There are no
changes to the functionality.
Let me know if you don't like some of those changes.

glfw/glx_context.c

@@ -433,7 +433,7 @@ void _glfwTerminateGLX(void)
 
 #define setAttrib(a, v) \
 { \
-    assert((size_t) (index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
+    assert(((size_t) index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
     attribs[index++] = a; \
     attribs[index++] = v; \
 }