use immediate evaluation for shell calls

This reworks the shell calls in the makefiles to use immediate
evaluation and should improve parallel building.

X-Gentoo-Bug: 289264
X-Gentoo-Bug-URL: http://bugs.gentoo.org/show_bug.cgi?id=289264

init.d/Makefile

@@ -9,8 +9,8 @@ _OLDNET_SH=	case "${MKOLDNET}" in \
 		[Yy][Ee][Ss]) echo "net.lo";; \
 		*) echo "";; \
 		esac
-_OLDNET!=	${_OLDNET_SH}
-_NET_LO=	${_OLDNET}$(shell ${_OLDNET_SH})
+_OLDNET:=	$(shell ${_OLDNET_SH})
+_NET_LO=	${_OLDNET}
 
 INSTALLAFTER=	_installafter_${_NET_LO}
 CLEANFILES+=	${_NET_LO}