Fix Windows specific environment settings on startup rather than checking
for special values on every getenv call.
As a side effect, this makes the patched environment (i.e. with properly
initialized TMPDIR and TERM) available to child processes.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>