package/proftpd: add sendfile

Enables sendfile to ProFTPD for zero-copy transfers.

Signed-off-by: Jared Bents <jared.bents@rockwellcollins.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/proftpd/proftpd.mk

@@ -20,6 +20,7 @@ PROFTPD_CONF_OPTS = \
 	--disable-ncurses \
 	--disable-facl \
 	--disable-dso \
+	--enable-sendfile \
 	--enable-shadow \
 	--with-gnu-ld