Support for completely OpenSSL-less builds. FSF considers distributing GPL
binaries with OpenSSL linked in as a legal problem so this is trouble
e.g. for Debian, or some people might not want to install OpenSSL
anyway. If you
make NO_OPENSSL=1
you get completely OpenSSL-less build, disabling --merge-order and using
Mozilla's SHA1 implementation.
Ported from Cogito.
Signed-off-by: Petr Baudis <pasky@ucw.cz> Signed-off-by: Junio C Hamano <junkio@cox.net>