Correct spelling mistakes.

code/renderergl1/tr_local.h

@@ -840,7 +840,7 @@ typedef struct {
 	int		msec;			// total msec for backend run
 } backEndCounters_t;
 
-// all state modified by the back end is seperated
+// all state modified by the back end is separated
 // from the front end state
 typedef struct {
 	trRefdef_t	refdef;
@@ -981,7 +981,7 @@ extern cvar_t	*r_measureOverdraw;		// enables stencil buffer overdraw measuremen
 extern cvar_t	*r_lodbias;				// push/pull LOD transitions
 extern cvar_t	*r_lodscale;
 
-extern cvar_t	*r_primitives;			// "0" = based on compiled vertex array existance
+extern cvar_t	*r_primitives;			// "0" = based on compiled vertex array existence
 										// "1" = glDrawElemet tristrips
 										// "2" = glDrawElements triangles
 										// "-1" = no drawing