Release: Don't assume that build host is Linux

Commit `Release: Allow non-Linux build hosts` enabled build of toolchain via
release.mk on macOS hosts, however many internal variables still used word
Linux in names. This patches renames all of those variables to use word
"host" instead of "linux". In some cases order of words in variables is
changed as well, so windows-specific variables are renamed to conform as
well.

Signed-off-by: Anton Kolesov <[email protected]>

Author: anthony-kolesov