configure.ac: check for HMAC_CTX_cleanup

OpenSSL version 0.9.6b and before defined the function HMAC_cleanup.
Newer versions define HMAC_CTX_cleanup.  Check for HMAC_CTX_cleanup and
fall back to HMAC_cleanup when the newer function is missing.

Signed-off-by: Reuben Hawkins <reubenhwk@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -345,6 +345,9 @@ all::
 # Define HAVE_CLOCK_GETTIME if your platform has clock_gettime in librt.
 #
 # Define HAVE_CLOCK_MONOTONIC if your platform has CLOCK_MONOTONIC in librt.
+#
+# Define NO_HMAC_CTX_CLEANUP if your OpenSSL is version 0.9.6b or earlier to
+# cleanup the HMAC context with the older HMAC_cleanup function.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -1077,6 +1080,9 @@ ifndef NO_OPENSSL
 	ifdef NEEDS_CRYPTO_WITH_SSL
 		OPENSSL_LIBSSL += -lcrypto
 	endif
+	ifdef NO_HMAC_CTX_CLEANUP
+		BASIC_CFLAGS += -DNO_HMAC_CTX_CLEANUP
+	endif
 else
 	BASIC_CFLAGS += -DNO_OPENSSL
 	BLK_SHA1 = 1

configure.ac

@@ -947,6 +947,10 @@ AC_CHECK_LIB([iconv], [locale_charset],
                      [CHARSET_LIB=-lcharset])])
 GIT_CONF_SUBST([CHARSET_LIB])
 #
+# Define NO_HMAC_CTX_CLEANUP=YesPlease if HMAC_CTX_cleanup is missing.
+AC_CHECK_LIB([crypto], [HMAC_CTX_cleanup],
+	[], [GIT_CONF_SUBST([NO_HMAC_CTX_CLEANUP], [YesPlease])])
+#
 # Define HAVE_CLOCK_GETTIME=YesPlease if clock_gettime is available.
 GIT_CHECK_FUNC(clock_gettime,
 	[HAVE_CLOCK_GETTIME=YesPlease],

git-compat-util.h

@@ -214,6 +214,9 @@ extern char *gitbasename(char *);
 #ifndef NO_OPENSSL
 #include <openssl/ssl.h>
 #include <openssl/err.h>
+#ifdef NO_HMAC_CTX_CLEANUP
+#define HMAC_CTX_cleanup HMAC_cleanup
+#endif
 #endif
 
 /* On most systems <netdb.h> would have given us this, but