Merge branch 'jh/mingw-openssl-sha1' into maint

Windows port wants to use OpenSSL's implementation of SHA-1
routines, so let them.

* jh/mingw-openssl-sha1:
  mingw: use OpenSSL's SHA-1 routines

Author: gitster

config.mak.uname

@@ -515,7 +515,6 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	OBJECT_CREATION_USES_RENAMES = UnfortunatelyNeedsTo
 	NO_REGEX = YesPlease
 	NO_PYTHON = YesPlease
-	BLK_SHA1 = YesPlease
 	ETAGS_TARGET = ETAGS
 	NO_INET_PTON = YesPlease
 	NO_INET_NTOP = YesPlease