gcrypt: add SHA-256 (fixes #7627)

(cherry picked from commit cf2106da2cae9ea158c2aec59ccb0c0754a8688b)

Conflicts:
	contrib/src/gcrypt/rules.mak

contrib/src/gcrypt/rules.mak

@@ -27,7 +27,7 @@ endif
 	#$(RECONF)
 	cd $< && $(HOSTVARS) ./configure $(HOSTCONF) \
 		--enable-ciphers=aes,des,rfc2268,arcfour \
-		--enable-digests=sha1,md5,rmd160,sha512 \
+		--enable-digests=sha1,md5,rmd160,sha256,sha512 \
 		--enable-pubkey-ciphers=dsa,rsa,ecc \
 		$(CONFIGURE_OPTS)
 	cd $< && $(MAKE) install