Allow ${PACKAGES} to be a symbolic link to another file system with more space.

*** 8.2/ports/Mk/bsd.port.mk	Thu May 19 11:39:42 2011
--- new/ports/Mk/bsd.port.mk	Thu May 19 11:41:06 2011
***************
*** 3983,3989 ****
  	fi
  	@__softMAKEFLAGS='${__softMAKEFLAGS:S/'/'\''/g}'; \
  	if ${PKG_CMD} -b ${PKGNAME} ${PKGFILE}; then \
! 		if [ -d ${PACKAGES} ]; then \
  			cd ${.CURDIR} && eval ${MAKE} $${__softMAKEFLAGS} package-links; \
  		fi; \
  	else \
--- 3983,3989 ----
  	fi
  	@__softMAKEFLAGS='${__softMAKEFLAGS:S/'/'\''/g}'; \
  	if ${PKG_CMD} -b ${PKGNAME} ${PKGFILE}; then \
! 		if [ -e ${PACKAGES} ]; then \
  			cd ${.CURDIR} && eval ${MAKE} $${__softMAKEFLAGS} package-links; \
  		fi; \
  	else \