gl_common: correct a type

We pass a pointer to a GLint to sscanf, using the %d format. That format
_always_ takes int, and not GLint (whatever the heck that is). If GLint
is always int, then it doesn't make a difference, but is still better
because it doesn't play russian roulette with pointers.

video/out/gl_common.c

@@ -499,7 +499,7 @@ void mpgl_load_functions(GL *gl, void *(*getProcAddress)(const GLubyte *),
         return;
     }
 
-    GLint major = 0, minor = 0;
+    int major = 0, minor = 0;
     const char *version = gl->GetString(GL_VERSION);
     sscanf(version, "%d.%d", &major, &minor);
     gl->version = MPGL_VER(major, minor);