* cygheap.h (cwdstuff::get_posix): Convert to const inline method just

	* cygheap.h (cwdstuff::get_posix): Convert to const inline method just
	returning pointer to posix path.
	(cwdstuff::reset_posix): Convert to non-inline method taking a wchar_t
	pointer.
	* path.cc (cwdstuff::set): Revert change from 2009-05-13.  Set posix
	to valid incoming path again.
	(cwdstuff::reset_posix): New implementation setting posix path from
	incoming wchar_t path.  Explain usage.
	(cwdstuff::get_posix): Drop implementation.
	(cwdstuff::get): Drop special case to handle empty posix path.
	* syscalls.cc (internal_setlocale): Store old posix cwd as wide char
	path.  Restore posix cwd using new charset.  Explain why.