wchar: compat mbsnrtowcs(), tests
amext-msvc: cleaups, safer mkdir
ctype: always activate macros

autoconf check is pointless, because compiler
can still complain about wrong usage.

So activate wrappers always, also remove arg,
so they are also used where function pointers are needed.
antimake: mkdir is not needed in ar_lib
msvc fixes
antimake: dont use readpath when loading extensions

Seems it's not reliable.
antimake: use printf instead of echo
msvc cleanup
base_win32: missing win32 includes
antimake: keep per-object mkdir always quiet
antimake: safer test result print
amext-msvc: random cleanups
m4/usual: fix ctype removal