Trouble with do-install

[Björn Lindström]

I'm trying for the first time to make a port that uses do-install in the
Makefile.

However, when I run 'make install' for the port, nothing that I can
perceive happens. I get no output, either.

Clues, please?

PORTNAME=           dtach
PORTVERSION=        0.6
CATEGORIES=         misc
MASTER_SITES=       ${MASTER_SITE_SOURCEFORGE}
MASTER_SITE_SUBDIR= dtach

MAINTAINER=         bkhl at elektrubadur.se
COMMENT=            A small program that emulates the detach feature of screen

GNU_CONFIGURE=      yes
ALL_TARGET=         dtach

MAN1=               dtach.1
PORTDOCS=           COPYING README dtach.spec

do-install:
	${INSTALL_PROGRAM} ${WRK_SRC}/dtach ${PREFIX}/bin
	${INSTALL_MAN} ${WRK_SRC}/dtach.1 ${MANPREFIX}/man/man1
.for f in ${PORTDOCS}
	${INSTALL_DATA} ${WRKSRC}/${f} ${DOCSDIR}
.endfor

.include <bsd.port.mk>