We only use this
1. if we have localeconv_l
2. to get the decimal point / thousands separator for numbers
So we can ignore all this and directly create a purely LC_NUMERIC locale.
This *was* more useful when we were in C++ and the printing functions
all relied on locale, but we only use this in printf and that only
extracts the number stuff.
* Fix build on NetBSD
Notably:
1. A typo in `f_flag` vs `f_flags` - this was probably never tested
2. Some pointless name differences - `st_mtimensec` vs
`st_mtime_nsec`
3. The big one: This said that LC_GLOBAL_LOCALE() was -1 "everywhere".
Well, not on NetBSD.
* ifdef for macos
This was previously limited to Linux predicated on the existence
of certain headers, but Rust just exposes those functions unconditionally. So
remove the check and just perform the mtime hack on Linux and Android.
