Fixed a comment in two test programs.

test/testgl2.c

@@ -59,7 +59,7 @@ static int LoadContext(GL_Context * data)
             return SDL_SetError("Couldn't load GL function %s: %s\n", #func, SDL_GetError()); \
         } \
     } while ( 0 );
-#endif /* _SDL_NOGETPROCADDR_ */
+#endif /* __SDL_NOGETPROCADDR__ */
 
 #include "../src/render/opengl/SDL_glfuncs.h"
 #undef SDL_PROC

test/testgles2.c

@@ -61,7 +61,7 @@ static int LoadContext(GLES2_Context * data)
             return SDL_SetError("Couldn't load GLES2 function %s: %s\n", #func, SDL_GetError()); \
         } \
     } while ( 0 );
-#endif /* _SDL_NOGETPROCADDR_ */
+#endif /* __SDL_NOGETPROCADDR__ */
 
 #include "../src/render/opengles2/SDL_gles2funcs.h"
 #undef SDL_PROC