ATTN: w32api maintainer, please remove mingw-specific code

[Nicholas Wourms]

Earnie or Danny,

The recent directx "reorganization" in the winsup/w32api dir has allowed
some mingw-only code to slip into the general build
(lib/directx/dxerr.c).  This causes a compile failure when building a
cygwin target.  Please have the author of the new code rectify this by
not using tchar.h functions.  Thanks in advance.

Cheers,
Nicholas