git.c:main() relies on the value of errno being set by the last attempt to
execute the command. However, if something goes awry in handle_alias(),
that assumption is wrong. So restore errno before returning from
handle_alias().
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <junkio@cox.net>