[PATCH 2/5] include: define _tcs* macros only when libc support exists.

[Kevin Puetz]

Sorry, apparently git quiltimport cuts at the --- too, so the motive I 
intended 
to explain on the submission (but not the git commit message) got left out.

---

wine-5.2 (c12089039637dec5e598ed1c41e707f057494242) changed to allow 
<tchar.h>
to be used without MSVCRT. This is useful for _TEXT(...) and _TCHAR 
typedefs,
but the _tcs* macros may still be unusable
 
Omitting them will be a clearer compile error when to not exist
than mapping them to e.g. wcs* functions which do not actually accept
a windows WCHAR (because WCHAR != wchar_t)