Corrected words in comments of test programs.

test/testatomic.c

@@ -91,7 +91,7 @@ void RunBasicTest()
 /* Tests semantics of atomic operations.  Also a stress test
  * to see if they are really atomic.
  *
- * Serveral threads adding to the same variable.
+ * Several threads adding to the same variable.
  * at the end the value is compared with the expected
  * and with a non-atomic counter.
  */

test/testdrawchessboard.c

@@ -75,7 +75,7 @@ main(int argc, char *argv[])
 		return 1;
 	}
 
-	/* Clear the rendering surface with the specidfied colour */
+	/* Clear the rendering surface with the specified color */
 	SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0);
 	SDL_RenderClear(renderer);
 
@@ -94,7 +94,7 @@ main(int argc, char *argv[])
 
 		DrawChessBoard(renderer);
 
-		/* Got everything on redering surface,
+		/* Got everything on rendering surface,
  		   now Update the drawing image on window screen */
 		SDL_UpdateWindowSurface(window);
 

test/testfile.c

@@ -92,8 +92,8 @@ main(int argc, char *argv[])
         RWOP_ERR_QUIT(rwops);
     printf("test1 OK\n");
 
-/* test 2 : check that inexistant file is not successfully opened/created when required */
-/* modes : r, r+ implie that file MUST exist
+/* test 2 : check that inexistent file is not successfully opened/created when required */
+/* modes : r, r+ imply that file MUST exist
    modes : a, a+, w, w+ checks that it succeeds (file may not exists)
 
  */