shaders: Mark screen_res as a uniform.

Author: CrossVR

res/gamedata/shaders/gl/stub_notransform_build.vs

@@ -1,7 +1,7 @@
 #include "common_iostructs.h"
 #include "iostructs\v_build.h"
 
-float4		screen_res;		// Screen resolution (x-Width,y-Height, zw - 1/resolution)
+uniform float4		screen_res;		// Screen resolution (x-Width,y-Height, zw - 1/resolution)
 
 //////////////////////////////////////////////////////////////////////////////////////////
 // Vertex

res/gamedata/shaders/gl/stub_notransform_filter.vs

@@ -1,7 +1,7 @@
 #include "common_iostructs.h"
 #include "iostructs\v_filter.h"
 
-float4		screen_res;		// Screen resolution (x-Width,y-Height, zw - 1/resolution)
+uniform float4		screen_res;		// Screen resolution (x-Width,y-Height, zw - 1/resolution)
 
 //////////////////////////////////////////////////////////////////////////////////////////
 // Vertex