use libtls in mail/msmtp

Hi,

msmtp has had libtls support for a while, so I think using
it would be preferable to GnuTLS. Here is an (untested) diff
which replaces GnuTLS with libtls.

diff --git a/mail/msmtp/Makefile b/mail/msmtp/Makefile
index 8559134974b..5bec6a05e28 100644
--- a/mail/msmtp/Makefile
+++ b/mail/msmtp/Makefile
@@ -8,19 +8,18 @@ HOMEPAGE =https://marlam.de/msmtp/
# GPLv3+
PERMIT_PACKAGE =Yes

-WANTLIB = c iconv idn2 intl gnutls
+WANTLIB = c iconv idn2 intl

MASTER_SITES =https://marlam.de/msmtp/releases/
EXTRACT_SUFX =.tar.xz

-LIB_DEPENDS =devel/libidn2 \
-security/gnutls
+LIB_DEPENDS =devel/libidn2

SEPARATE_BUILD =Yes
CONFIGURE_STYLE =gnu
CONFIGURE_ARGS =--with-libgsasl=no \
--with-libidn=yes \
---with-tls=gnutls \
+--with-tls=libtls \
--without-libsecret

post-install:

---
Nihal