Merge branch 'ba/osxkeychain-updates' into next

Update osxkeychain backend with features required for the recent
credential subsystem.

* ba/osxkeychain-updates:
  osxkeychain: store new attributes
  osxkeychain: erase matching passwords only
  osxkeychain: erase all matching credentials
  osxkeychain: replace deprecated SecKeychain API

contrib/credential/osxkeychain/Makefile

@@ -8,7 +8,8 @@ CFLAGS = -g -O2 -Wall
 -include ../../../config.mak
 
 git-credential-osxkeychain: git-credential-osxkeychain.o
-	$(CC) $(CFLAGS) -o $@ $< $(LDFLAGS) -Wl,-framework -Wl,Security
+	$(CC) $(CFLAGS) -o $@ $< $(LDFLAGS) \
+		-framework Security -framework CoreFoundation
 
 git-credential-osxkeychain.o: git-credential-osxkeychain.c
 	$(CC) -c $(CFLAGS) $<