[RFC PATCH 11/12] hash: add an SHA-256 implementation using OpenSSL

["brian m. carlson" <sandals@crustytoothpaste.net>]

We already have OpenSSL routines available for SHA-1, so add routines
for SHA-256 as well.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 Makefile | 7 +++++++
 hash.h   | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/Makefile b/Makefile
index 86867af083..8b7df4dfc5 100644
--- a/Makefile
+++ b/Makefile
@@ -183,6 +183,8 @@ all::
 #
 # Define GCRYPT_SHA256 to use the SHA-256 routines in libgcrypt.
 #
+# Define OPENSSL_SHA256 to use the SHA-256 routines in OpenSSL.
+#
 # Define NEEDS_CRYPTO_WITH_SSL if you need -lcrypto when using -lssl (Darwin).
 #
 # Define NEEDS_SSL_WITH_CRYPTO if you need -lssl when using -lcrypto (Darwin).
@@ -1628,6 +1630,10 @@ endif
 endif
 endif
 
+ifdef OPENSSL_SHA256
+	EXTLIBS += $(LIB_4_CRYPTO)
+	BASIC_CFLAGS += -DSHA256_OPENSSL
+else
 ifdef GCRYPT_SHA256
 	BASIC_CFLAGS += -DSHA256_GCRYPT
 	EXTLIBS += -lgcrypt
@@ -1635,6 +1641,7 @@ else
 	LIB_OBJS += sha256/block/sha256.o
 	BASIC_CFLAGS += -DSHA256_BLK
 endif
+endif
 
 ifdef SHA1_MAX_BLOCK_SIZE
 	LIB_OBJS += compat/sha1-chunked.o
diff --git a/hash.h b/hash.h
index 9df562f2f6..9df06d56b4 100644
--- a/hash.h
+++ b/hash.h
@@ -17,6 +17,8 @@
 
 #if defined(SHA256_GCRYPT)
 #include "sha256/gcrypt.h"
+#elif defined(SHA256_OPENSSL)
+#include <openssl/sha.h>
 #else
 #include "sha256/block/sha256.h"
 #endif