Makefile: set NO_OPENSSL on macOS by default

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: NTorsten Bögershausen <tboegi@web.de>
Signed-off-by: NLars Schneider <larsxschneider@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Makefile

@@ -1023,6 +1023,7 @@ ifeq ($(uname_S),Darwin)
 		endif
 	endif
 	ifndef NO_APPLE_COMMON_CRYPTO
+		NO_OPENSSL = YesPlease
 		APPLE_COMMON_CRYPTO = YesPlease
 		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
 	endif