BLI_strncpy_wchar_from_utf8 made the assumption that
wchar_t is UTF-32 bit regardless of environment, while
this holds true on both mac and linux, on windows
wchar_t is actually actually UTF-16.
This resulted in the upper 16 bits being dropped from
from some string conversions and prevented blender
from starting when installed in a path with unicode
code-points over 0xffff.
There was also a fair bit of code duplication between
BLI_strncpy_wchar_from_utf8 and BLI_str_utf8_as_unicode_and_size
this change essentially removes all logic from
BLI_strncpy_wchar_from_utf8 and calls the right function
for the right environment.
Reviewed By: brecht , Robert Guetzkow
Differential Revision: https://developer.blender.org/D9822
5496d8cd36