diff --git a/Makefile.inc1 b/Makefile.inc1
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -1748,16 +1748,10 @@
 BUILDKERNELS+= dummy
 .endif
 .for _kernel in ${KERNCONF}
-.if !defined(_MKSHOWCONFIG) && exists(${KERNCONFDIR}/${_kernel})
 BUILDKERNELS+=	${_kernel}
 .if empty(INSTALLKERNEL) && !defined(NO_INSTALLKERNEL)
 INSTALLKERNEL= ${_kernel}
 .endif
-.else
-.if make(buildkernel)
-.error Missing KERNCONF ${KERNCONFDIR}/${_kernel}
-.endif
-.endif
 .endfor
 
 _cleankernobj_fast_depend_hack: .PHONY
@@ -1782,6 +1776,29 @@
 _BUILDKERNEL_START!= date '+%s'
 .endif
 
+# Construct a variant configuration file
+.if make(kernconffile)
+.if exists(${KERNCONFDIR}/${KERNCONF})
+kernconffile:
+	cp ${KERNCONFDIR}/${KERNCONF} ${KRNLOBJDIR}/${KERNCONFTGT}
+.else
+KERNCONFPREFIX=${KERNCONF:C/-[^-]+$//}
+KERNCONFSUFFIX=${KERNCONF:C/^.*-//}
+kernconffile:
+.if ${KERNCONF} == ${KERNCONFPREFIX}
+.error Missing KERNCONF ${KERNCONFDIR}/${KERNCONF}
+.endif
+	${_+_}${MAKE} -C ${.CURDIR} -f Makefile.inc1 kernconffile \
+	    KERNCONF=${KERNCONFPREFIX} KERNCONFTGT=${KERNCONFTGT}
+	( \
+		echo "# ${KERNCONF} -- automatically generated configuration file"; \
+		echo "include ${KERNCONFPREFIX}"; \
+		echo "include \"std.${KERNCONFSUFFIX:tl}\""; \
+		echo "ident ${KERNCONF}" \
+	) > ${KRNLOBJDIR}/${KERNCONFTGT}/${KERNCONF}
+.endif
+.endif
+
 #
 # buildkernel
 #
@@ -1804,11 +1821,14 @@
 	@echo "--------------------------------------------------------------"
 	@echo ">>> stage 1: configuring the kernel"
 	@echo "--------------------------------------------------------------"
+	mkdir -p ${KRNLOBJDIR}/${_kernel}
+	${_+_}${MAKE} -C ${.CURDIR} -f Makefile.inc1 kernconffile \
+	    KERNCONF=${_kernel} KERNCONFTGT=${_kernel}
 	cd ${KRNLCONFDIR}; \
 		PATH=${TMPPATH:Q} \
 		    config ${CONFIGARGS} -d ${KRNLOBJDIR}/${_kernel} \
-			-I '${KERNCONFDIR}' -I '${KRNLCONFDIR}' \
-			'${KERNCONFDIR}/${_kernel}'
+			-I '${KERNOBJDIR}/${_kernel}' -I '${KRNLCONFDIR}' \
+			'${KRNLOBJDIR}/${_kernel}/${_kernel}'
 .endif
 .if ${MK_CLEAN} == "yes" && !defined(NO_KERNELCLEAN)
 	@echo