Index: head/sys/conf/kern.post.mk
===================================================================
--- head/sys/conf/kern.post.mk
+++ head/sys/conf/kern.post.mk
@@ -364,6 +364,9 @@
 	    --output-target ${EMBEDFS_FORMAT.${MACHINE_ARCH}} \
 	    --binary-architecture ${EMBEDFS_ARCH.${MACHINE_ARCH}} \
 	    ${MFS_IMAGE} ${.TARGET}
+	# Provide set of two distinct regexp to match for GCC (first three)
+	# and for CLANG >= 3.8.0 (last three). First three should be removed
+	# once support for GCC and CLANG < 3.8.0 is abandoned.
 	${OBJCOPY} \
 	    --rename-section .data=mfs,contents,alloc,load,readonly,data \
 	    --redefine-sym \
@@ -372,6 +375,12 @@
 		_binary_${MFS_IMAGE:C,[^[:alnum:]],_,g}_start=mfs_root \
 	    --redefine-sym \
 		_binary_${MFS_IMAGE:C,[^[:alnum:]],_,g}_end=mfs_root_end \
+	    --redefine-sym \
+		_binary_${MFS_IMAGE:C,[^-/[:alnum:]],_,g}_size=__mfs_root_size \
+	    --redefine-sym \
+		_binary_${MFS_IMAGE:C,[^-/[:alnum:]],_,g}_start=mfs_root \
+	    --redefine-sym \
+		_binary_${MFS_IMAGE:C,[^-/[:alnum:]],_,g}_end=mfs_root_end \
 	    ${.TARGET}
 .endif
 .endif