properly pass current locale to *_l functions when used internally

this change is presently non-functional since the callees do not yet
use their locale argument for anything.

fix semantically incorrect use of LC_GLOBAL_LOCALE

LC_GLOBAL_LOCALE refers to the global locale, controlled by setlocale,
not the thread-local locale in effect which these functions should be
using. neither LC_GLOBAL_LOCALE nor 0 has an argument to the *_l
functions has behavior defined by the standard, but 0 is a more
logical choice for requesting the callee to lookup the current locale.
in the future I may move the current locale lookup the the caller (the
non-_l-suffixed wrapper).

at this point, all of the locale logic is dummied out, so no harm was
done, but it should at least avoid misleading usage.

prepare strcoll/wcscoll for LC_COLLATE support and add ABI symbols

initial check-in, version 0.5.0