Apple removed the OpenSSL header files in macOS 10.11 and above. OpenSSL
was deprecated since macOS 10.7.
Set `NO_OPENSSL` and `APPLE_COMMON_CRYPTO` to `YesPlease` as default for
macOS. It is possible to override this and use OpenSSL by defining
`NO_APPLE_COMMON_CRYPTO`.
Original-patch-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>