There were a couple of typos in r12-4070 and r12-4071 which don't show
up when building for POSIX targets.

libstdc++-v3/ChangeLog:

	* src/c++17/fs_ops.cc (create_directory): Fix typo in enum name.
	* src/filesystem/ops-common.h (__last_system_error): Add
	explicit cast to avoid narrowing conversion.
	(do_space): Fix type in function name.

Tested x86_64-linux. Committed to trunk.