Comment 1 for bug 518852

This also happens on a NetBSD system (one of the buildslaves for Tahoe-LAFS):

In file included from src/libtom/tomcrypt.h:72,
                 from src/libtom/tomcrypt_des.c:11,
                 from src/DES.c:32:
src/libtom/tomcrypt_pk.h:502: error: conflicting types for 'wchar_t'
/usr/include/stdlib.h:52: error: previous declaration of 'wchar_t' was here
error: Setup script exited with error: command 'cc' failed with exit status 1

If PyCrypto does not depend on the functions that use wchar_t, then it may be better to disable that code rather than adding _WCHAR_T_DECLARED to the checks.