ref: gl: add size argument to COM_Default/ReplaceExtension calls

ref/gl/gl_backend.c

@@ -578,9 +578,8 @@ qboolean VID_CubemapShot( const char *base, uint size, const float *vieworg, qbo
 	r_shot->buffer = buffer;
 
 	// make sure what we have right extension
-	Q_strncpy( basename, base, MAX_STRING );
-	COM_StripExtension( basename );
-	COM_DefaultExtension( basename, ".tga" );
+	Q_strncpy( basename, base, sizeof( basename ));
+	COM_ReplaceExtension( basename, ".tga", sizeof( basename ));
 
 	// write image as 6 sides
 	result = gEngfuncs.FS_SaveImage( basename, r_shot );