* libc/include/stdint.h (__EXP): Rename to __STDINT_EXP
and do not #undef the macro after it is used. Fix typos.
Also change 64-bit constants to use the __have_long64 and
__have_longlong64 flags to determine if long or long long
constants should be used.
* libc/include/inttypes.h: Include stddef.h to get wchar_t
type defined.