fix clang warnings, directly include wtypes.h (#4097)

fix clang warnings, directly include wtypes.h (#4097)

* build: clang use -Wno-unused-command-line-argument

With clang 5.0 builds are quite noisy otherwise.

* Directly include wtypes.h

Directly include winpr/wtypes.h where _fseeki64 or _ftelli64 is used.

* fix build warnings with clang 5

clang version: 5.0.0-svn310678-1~exp1 (branches/release_50)
Warning: parentheses-equality

* fix build warnings with clang 5

clang version: 5.0.0-svn310678-1~exp1 (branches/release_50)
Warning: tautological-compare

* fix build warnings with clang 5

clang version: 5.0.0-svn310678-1~exp1 (branches/release_50)
Warning:
incompatible pointer types passing 'size_t *' (aka 'unsigned
long *') to parameter of type 'UINT32 *' (aka 'unsigned int *')
[-Wincompatible-pointer-types]