I agree, but I was asking about SSL support, because I think that postfix 
  from the base system doesn't support this, If I'm not wrong, right?

  BTW why postfix requires SASL libraries to enable SSL support?

Postfix with SSL/TLS doesn't require SASL.

Right now, v6 and tls support are linked, because they are in the same
patch.  SASL support is part of postfix, and pkgsrc just buildlinks in
sasl libs and enables them.

So if we applied the v6/tls patch to in-tree postfix, it wouldn't need
anything from pkgsrc.  But this patch is apparently somewhat
controversial - or it would just be part of postfix.

See the following from mail/postfix/Makefile:

----------------------------------------

.if defined(POSTFIX_USE_INET6) && ${POSTFIX_USE_INET6} == "YES"
.  include "../../security/openssl/buildlink3.mk"
PATCHFILES+=		tls+ipv6-1.24-pf-2.0.20.patch.gz
PATCH_SITES+=		ftp://ftp.stack.nl/pub/postfix/tls+ipv6/1.24/
PATCH_DIST_STRIP=	-p1

CCARGS+=	-DHAS_SSL
AUXLIBS+=	-L${BUILDLINK_PREFIX.openssl}/lib			\
		-Wl,${RPATH_FLAG}${BUILDLINK_PREFIX.openssl}/lib	\
		-lssl -lcrypto

PLIST_SRC+=	${PKGDIR}/PLIST.tls
MESSAGE_SRC+=	${PKGDIR}/MESSAGE.tls
.endif

----------------------------------------

.if defined(USE_SASL2) && ${USE_SASL2} == "YES"
USING_SASL=	YES
.  include "../../security/cyrus-sasl2/buildlink3.mk"
CCARGS+=	-DUSE_SASL2_AUTH
AUXLIBS+=	-L${BUILDLINK_PREFIX.cyrus-sasl}/lib			\
		-Wl,${RPATH_FLAG}${BUILDLINK_PREFIX.cyrus-sasl}/lib	\
		-lsasl2
.elif defined(USE_SASL) && ${USE_SASL} == "YES"
USING_SASL=YES
.  include "../../security/cyrus-sasl/buildlink3.mk"
CCARGS+=	-DUSE_SASL_AUTH
AUXLIBS+=	-L${BUILDLINK_PREFIX.cyrus-sasl}/lib			\
		-Wl,${RPATH_FLAG}${BUILDLINK_PREFIX.cyrus-sasl}/lib	\
		-lsasl
.endif

.if defined(USING_SASL)
PLIST_SRC+=	${PKGDIR}/PLIST.sasl
MESSAGE_SRC+=	${PKGDIR}/MESSAGE.sasl
MESSAGE_SUBST+=	PKG_SYSCONFDIR=${PKG_SYSCONFDIR}
.endif




-- 
        Greg Troxel <gdt@ir.bbn.com>