`_lock_file`, `_unlock_file`, and `_fgetc_nolock`

[glebm]

Newer versions of libfmt need these 3 Windows functions, would it be possible to add them?

[thrimbor]

Hm, that would require some rework in PDCLib, it doesn't currently expose the function without locks, and I haven't yet looked too much into the semantics either.
For the moment it's probably easier to add a check for nxdk to that ifdef and make libfmt use the fallback version of that class (looks like FMT_USE_FALLBACK_FILE will do that)

[glebm]

The functions are no longer required by libfmt but implementing them will improve performance