[PATCH v4 3/3] cache.h: eliminate SHA-1 deprecation warnings on OS X 10.8

Mac OS X Mountain Lion prints warnings when building git:

	warning: 'SHA1_Init' is deprecated
	(declared at /usr/include/openssl/sha.h:121)

Silence the warnings by using the CommonCrytpo SHA-1
functions for SHA1_Init(), SHA1_Update(), and SHA1_Final().

Add a COMMON_DIGEST_SHA1 option to the Makefile to allow
choosing this implementation and define it by default on Darwin.

Define COMMON_DIGEST_FOR_OPENSSL to enable the OpenSSL
compatibility macros in CommonDigest.h.

Helped-by: Eric Sunshine [off-list ref]
Signed-off-by: David Aguilar <redacted>
---
Changes since last round:
COMMON_DIGEST_FOR_OPENSSL is used to enable the compatibility macros.

 Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Makefile b/Makefile
index a0f7afc..29c02ed 100644
--- a/Makefile
+++ b/Makefile

@@ -1055,6 +1055,7 @@ ifeq ($(uname_S),Darwin)
 		endif
 	endif
 	COMMON_DIGEST_HMAC = YesPlease
+	COMMON_DIGEST_SHA1 = YesPlease
 	NO_REGEX = YesPlease
 	PTHREAD_LIBS =
 endif

@@ -1390,10 +1391,15 @@ ifdef PPC_SHA1
 	LIB_OBJS += ppc/sha1.o ppc/sha1ppc.o
 	LIB_H += ppc/sha1.h
 else
+ifdef COMMON_DIGEST_SHA1
+	BASIC_CFLAGS += -DCOMMON_DIGEST_FOR_OPENSSL
+	SHA1_HEADER = <CommonCrypto/CommonDigest.h>
+else
 	SHA1_HEADER = <openssl/sha.h>
 	EXTLIBS += $(LIB_4_CRYPTO)
 endif
 endif
+endif
 
 ifdef COMMON_DIGEST_HMAC
 	BASIC_CFLAGS += -DCOMMON_DIGEST_FOR_HMAC

-- 
1.8.3.rc1.52.g872cb7b