The real EUCs do not need the GB18030 hack.
Supress warnings about iconv prototype mismatch.
Restore the initial state at the end of line.

This matters for stateful encodings like iso-2022-jp.
Tweak the cmake file a little bit.
Fix ICONV_TRADITIONAL check for clang

necessary for OS X 10.8.2 XCode 4.6

edit: gcc42 breaks under -Wno-dangling-else; make it clang-only.
b64_ntop/pton is in not in libc on OSX
Factor out the steady time and the system time.
Implement timepoint_* for Mac OS X.