[Bug preprocessor/50387] Doesn't process "_Pragma" when expanding a token sequence for #include

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=50387

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Simplified testcase:
```
#define GET(H) _Pragma("") <H>
#include GET(stdio.h)
```

Both MSVC and clang are able to handle this.

ICC rejects it for the same reason as GCC.