Makefile: iconv() on Darwin has the old interface

The libiconv on Darwin uses the old iconv() interface (2nd argument is a
const char **, instead of a char **).  Add OLD_ICONV to the Darwin
variable definitions to handle this.

Signed-off-by: Arjen Laarhoven <[email protected]>
Acked-by: Brian Gernhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ArjenL

Makefile

@@ -356,6 +356,7 @@ endif
 ifeq ($(uname_S),Darwin)
 	NEEDS_SSL_WITH_CRYPTO = YesPlease
 	NEEDS_LIBICONV = YesPlease
+	OLD_ICONV = UnfortunatelyYes
 	NO_STRLCPY = YesPlease
 endif
 ifeq ($(uname_S),SunOS)