Index: head/sys/conf/config.mk
===================================================================
--- head/sys/conf/config.mk	(revision 296769)
+++ head/sys/conf/config.mk	(revision 296770)
@@ -1,54 +1,55 @@
 # $FreeBSD$
 #
 # Common code to marry kernel config(8) goo and module building goo.
 #
 
 # Generate options files that otherwise would be built
 # in substantially similar ways through the tree. Move
 # the code here when they all produce identical results
 # (or should)
 .if !defined(KERNBUILDDIR)
 opt_bpf.h:
 	echo "#define DEV_BPF 1" > ${.TARGET}
 .if ${MK_INET_SUPPORT} != "no"
 opt_inet.h:
 	@echo "#define INET 1" > ${.TARGET}
 	@echo "#define TCP_OFFLOAD 1" >> ${.TARGET}
 .endif
 .if ${MK_INET6_SUPPORT} != "no"
 opt_inet6.h:
 	@echo "#define INET6 1" > ${.TARGET}
 .endif
 .if ${MK_EISA} != "no"
 opt_eisa.h:
 	@echo "#define DEV_EISA 1" > ${.TARGET}
 .endif
 opt_mrouting.h:
 	echo "#define MROUTING 1" > ${.TARGET}
 opt_natm.h:
 	echo "#define NATM 1" > ${.TARGET}
 opt_scsi.h:
 	echo "#define SCSI_DELAY 15000" > ${.TARGET}
 opt_wlan.h:
 	echo "#define IEEE80211_DEBUG 1" > ${.TARGET}
 	echo "#define IEEE80211_AMPDU_AGE 1" >> ${.TARGET}
 	echo "#define IEEE80211_SUPPORT_MESH 1" >> ${.TARGET}
 KERN_OPTS.i386=NEW_PCIB DEV_PCI
 KERN_OPTS.pc98=NEW_PCIB DEV_PCI
 KERN_OPTS.amd64=NEW_PCIB DEV_PCI
 KERN_OPTS.powerpc=NEW_PCIB DEV_PCI
 KERN_OPTS=MROUTING NATM IEEE80211_DEBUG \
 	IEEE80211_AMPDU_AGE IEEE80211_SUPPORT_MESH DEV_BPF \
 	${KERN_OPTS.${MACHINE}} ${KERN_OPTS_EXTRA}
 .if ${MK_INET_SUPPORT} != "no"
 KERN_OPTS+= INET TCP_OFFLOAD
 .endif
 .if ${MK_INET6_SUPPORT} != "no"
 KERN_OPTS+= INET6
 .endif
 .if ${MK_EISA} != "no"
 KERN_OPTS+= DEV_EISA
 .endif
-.else
+.elif !defined(KERN_OPTS)
 KERN_OPTS!=cat ${KERNBUILDDIR}/opt*.h | awk '{print $$2;}' | sort -u
+.export KERN_OPTS
 .endif
Index: head/sys/conf/kern.opts.mk
===================================================================
--- head/sys/conf/kern.opts.mk	(revision 296769)
+++ head/sys/conf/kern.opts.mk	(revision 296770)
@@ -1,157 +1,160 @@
 # $FreeBSD$
 
 # Options set in the build system that affect the kernel somehow.
 
 #
 # Define MK_* variables (which are either "yes" or "no") for users
 # to set via WITH_*/WITHOUT_* in /etc/src.conf and override in the
 # make(1) environment.
 # These should be tested with `== "no"' or `!= "no"' in makefiles.
 # The NO_* variables should only be set by makefiles for variables
 # that haven't been converted over.
 #
 
 # Note: bsd.own.mk must be included before the rest of kern.opts.mk to make
 # building on 10.x and earlier work. This should be removed when that's no
 # longer supported since it confounds the defaults (since it uses the host's
 # notion of defaults rather than what's default in current when building
 # within sys/modules).
 .include <bsd.own.mk>
 
 # These options are used by the kernel build process (kern.mk and kmod.mk)
 # They have to be listed here so we can build modules outside of the
 # src tree.
 
 __DEFAULT_YES_OPTIONS = \
     AUTOFS \
     BHYVE \
     BLUETOOTH \
     CCD \
     CDDL \
     CRYPT \
     CUSE \
     FORMAT_EXTENSIONS \
     INET \
     INET6 \
     IPFILTER \
     ISCSI \
     KERNEL_SYMBOLS \
     NETGRAPH \
     PF \
     SOURCELESS_HOST \
     SOURCELESS_UCODE \
     USB_GADGET_EXAMPLES \
     ZFS
 
 __DEFAULT_NO_OPTIONS = \
     EISA \
     FAST_DEPEND \
     NAND \
     OFED
 
 # Enable FAST_DEPEND by default for the meta build.
 .if !empty(.MAKE.MODE:Unormal:Mmeta)
 __DEFAULT_YES_OPTIONS+=	FAST_DEPEND
 __DEFAULT_NO_OPTIONS:=	${__DEFAULT_NO_OPTIONS:NFAST_DEPEND}
 .endif
 
 # Some options are totally broken on some architectures. We disable
 # them. If you need to enable them on an experimental basis, you
 # must change this code.
 # Note: These only apply to the list of modules we build by default
 # and sometimes what is in the opt_*.h files by default.
 # Kernel config files are unaffected, though some targets can be
 # affected by KERNEL_SYMBOLS, FORMAT_EXTENSIONS, CTF and SSP.
 
 # Things that don't work based on the CPU
 .if ${MACHINE_CPUARCH} == "arm"
 BROKEN_OPTIONS+= ZFS
 . if ${MACHINE_ARCH:Marmv6*} == ""
 BROKEN_OPTIONS+= CDDL
 . endif
 .endif
 
 .if ${MACHINE_CPUARCH} == "mips"
 BROKEN_OPTIONS+= CDDL ZFS
 .endif
 
 .if ${MACHINE_CPUARCH} == "powerpc" && ${MACHINE_ARCH} == "powerpc"
 BROKEN_OPTIONS+= ZFS
 .endif
 
 # Things that don't work because the kernel doesn't have the support
 # for them.
 .if ${MACHINE} != "i386"
 BROKEN_OPTIONS+= EISA
 .endif
 
 .if ${MACHINE} != "i386" && ${MACHINE} != "amd64"
 BROKEN_OPTIONS+= OFED
 .endif
 
 # expanded inline from bsd.mkopt.mk to avoid share/mk dependency
 
 # Those that default to yes
 .for var in ${__DEFAULT_YES_OPTIONS}
 .if !defined(MK_${var})
 .if defined(WITHOUT_${var})			# WITHOUT always wins
 MK_${var}:=	no
 .else
 MK_${var}:=	yes
 .endif
 .else
 .if ${MK_${var}} != "yes" && ${MK_${var}} != "no"
 .error "Illegal value for MK_${var}: ${MK_${var}}"
 .endif
 .endif # !defined(MK_${var})
 .endfor
 .undef __DEFAULT_YES_OPTIONS
 
 # Those that default to no
 .for var in ${__DEFAULT_NO_OPTIONS}
 .if !defined(MK_${var})
 .if defined(WITH_${var}) && !defined(WITHOUT_${var}) # WITHOUT always wins
 MK_${var}:=	yes
 .else
 MK_${var}:=	no
 .endif
 .else
 .if ${MK_${var}} != "yes" && ${MK_${var}} != "no"
 .error "Illegal value for MK_${var}: ${MK_${var}}"
 .endif
 .endif # !defined(MK_${var})
 .endfor
 .undef __DEFAULT_NO_OPTIONS
 
 #
 # MK_* options which are always no, usually because they are
 # unsupported/badly broken on this architecture.
 #
 .for var in ${BROKEN_OPTIONS}
 MK_${var}:=	no
 .endfor
 .undef BROKEN_OPTIONS
 #end of bsd.mkopt.mk expanded inline.
 
 #
 # MK_*_SUPPORT options which default to "yes" unless their corresponding
 # MK_* variable is set to "no".
 #
 .for var in \
     INET \
     INET6
 .if defined(WITHOUT_${var}_SUPPORT) || ${MK_${var}} == "no"
 MK_${var}_SUPPORT:= no
 .else
 .if defined(KERNBUILDDIR)	# See if there's an opt_foo.h
+.if !defined(OPT_${var})
 OPT_${var}!= cat ${KERNBUILDDIR}/opt_${var:tl}.h; echo
+.export OPT_${var}
+.endif
 .if ${OPT_${var}} == ""		# nothing -> no
 MK_${var}_SUPPORT:= no
 .else
 MK_${var}_SUPPORT:= yes
 .endif
 .else				# otherwise, yes
 MK_${var}_SUPPORT:= yes
 .endif
 .endif
 .endfor