[PATCH] Missing calls for #elif PPCallback.

Hello.

It seems that the #elif preprocessor callback is not called in code such as the following, where the #if condition evaluates to false:

#if UNDEF
#elif DEF
#endif

The attached patch fixes it.
Also added a testcase.

Enea.

Elif-Callback.patch (4.53 KB)

Ping.

Ping^2.