This commit refactors uv_os_homedir() to to use uv_os_getenv()
to retrieve the USERPROFILE environment variable. This removes
a fair amount of duplicated code, while introducing the following
changes:
1. The function no longer returns UV_EIO when USERPROFILE is
longer than MAX_PATH. This can be reinstated by adding a
check for r == 0 && *size >= MAX_PATH.
2. The USERPROFILE string is now a char*, meaning that it must
be converted from utf8 to utf16 by uv_os_getenv().
Refs: https://github.com/libuv/libuv/pull/1760
PR-URL: https://github.com/libuv/libuv/pull/1761
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
502decd620