This is because of some shell quoting lossage.  Basically, we now
have:

_VALID_GS+=     ghostscript-gnu>=${GHOSTSCRIPT_REQD}
_VALID_GS+=     ghostscript-gnu-x11>=${GHOSTSCRIPT_REQD}
_VALID_GS+=     ghostscript-gnu-no11>=${GHOSTSCRIPT_REQD}
_GS_DEPENDS!=   ${ECHO} '${_VALID_GS}' | ${SED} -e "s:^ *::" -e "s: :,:g"
GHOSTSCRIPT_DEPENDS=    {${_GS_DEPENDS}}:${_GS_PKGSRCDIR}
MAKEFLAGS+=             GHOSTSCRIPT_DEPENDS="${GHOSTSCRIPT_DEPENDS}"

which expands to:

_VALID_GS= ghostscript-gnu>=6.01 ghostscript-gnu-x11>=6.01 ghostscript>=6.01
_GS_DEPENDS=ghostscript-gnu>=6.01,ghostscript-gnu-x11>=6.01,ghostscript>=6.01
GHOSTSCRIPT_DEPENDS={ghostscript-gnu>=6.01,ghostscript-gnu-x11>=6.01,ghostscript>=6.01}:../../print/ghostscript-gnu
MAKEFLAGS=OPSYS=NetBSD OS_VERSION=1.6H LOWER_OPSYS=netbsd DIGEST=/usr/pkg/bin/digest DIGEST_VERSION="20010807" PKGTOOLS_VERSION="20020827" GHOSTSCRIPT_DEPENDS="{ghostscript-gnu>=6.01,ghostscript-gnu-x11>=6.01,ghostscript>=6.01}:../../print/ghostscript-gnu" [buildlink shite elided]

and is passed down to subshells via:

PKG_ARGS_COMMON+=       -P "`${MAKE} ${MAKEFLAGS} run-depends-list PACKAGE_DEPENDS_QUICK=true | ${SORT} -u`"
                        CLEAN_DEPENDS_LIST_SEEN=" $$dir `cd ${.CURDIR} ; cd $$dir && ${MAKE} ${MAKEFLAGS} CLEAN_DEPENDS_LIST_SEEN="$$CLEAN_DEPENDS_LIST_SEEN" CLEAN_DEPENDS_LIST_TOP=NO clean-depends-list`";\
                list="`${MAKE} ${MAKEFLAGS} run-depends-list PACKAGE_DEPENDS_QUICK=true ECHO_MSG=${TRUE} | ${SORT} -u`" ; \

The result is fairly obvious.  The shell ends up trying to redirect.