Enable sidebar support in mutt (#598)

This enables the popular sidebar feature in mutt. It will still be [disabled by
default](http://www.mutt.org/doc/manual/#sidebar) and has to be [enabled
in the .muttrc](https://wiki.archlinux.org/index.php/Mutt#Mutt-Sidebar).

packages/mutt/build.sh

@@ -1,11 +1,11 @@
 TERMUX_PKG_HOMEPAGE=http://www.mutt.org/
 TERMUX_PKG_DESCRIPTION="Mail client with patches from neomutt"
 TERMUX_PKG_VERSION=1.7.2
-TERMUX_PKG_BUILD_REVISION=1
+TERMUX_PKG_BUILD_REVISION=2
 TERMUX_PKG_SRCURL=ftp://ftp.mutt.org/pub/mutt/mutt-${TERMUX_PKG_VERSION}.tar.gz
 TERMUX_PKG_SHA256=1553501687cd22d5b8aaee4dc5a7d9dcf6cc61d7956f6aabaadd252d10cd5ff9
 TERMUX_PKG_DEPENDS="libandroid-support, ncurses, gdbm, openssl, libsasl"
-TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--enable-smtp --enable-imap --enable-pop --with-mailpath=$TERMUX_PREFIX/var/mail --with-ssl --enable-compressed --without-idn --enable-hcache --with-sasl"
+TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--enable-smtp --enable-imap --enable-pop --with-mailpath=$TERMUX_PREFIX/var/mail --with-ssl --enable-compressed --without-idn --enable-hcache --with-sasl --enable-sidebar"
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS+=" --with-exec-shell=$TERMUX_PREFIX/bin/sh"
 # The mutt autoconf guesses no for working (v)snprintf and uses broken local versions - avoid that:
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS+=" mutt_cv_c99_snprintf=yes mutt_cv_c99_vsnprintf=yes"