Hello,
in multimedia/banshee-devel/Makefile
> LIB_DEPENDS+= mtp.11:${PORTSDIR}/audio/libmtp
What is "mtp.11" ?
IMHO, this may be become "${LOCALBASE}/lib/libmtp.so.9" or
instead of LIB_DEPENDS, using LIB_PC_DEPENDS, like
LIB_PC_DEPENDS+=${LOCALBASE}/libdata/pkgconfig/libmtp.pc .
Sincerely