Modular rendering system. Patch by use.less01

This might break MSVC builds. I'll take care of it later

code/renderer/tr_world.c

@@ -547,7 +547,7 @@ qboolean R_inPVS( const vec3_t p1, const vec3_t p2 ) {
 	byte	*vis;
 
 	leaf = R_PointInLeaf( p1 );
-	vis = CM_ClusterPVS( leaf->cluster );
+	vis = ri.CM_ClusterPVS( leaf->cluster ); // why not R_ClusterPVS ??
 	leaf = R_PointInLeaf( p2 );
 
 	if ( !(vis[leaf->cluster>>3] & (1<<(leaf->cluster&7))) ) {