diff --git a/Mk/Uses/elfctl.mk b/Mk/Uses/elfctl.mk
--- a/Mk/Uses/elfctl.mk
+++ b/Mk/Uses/elfctl.mk
@@ -1,26 +1,39 @@
-# Change an ELF binary's feature control note
+# Set ELF binary feature control notes
 #
 # Feature:	elfctl
-# Usage:	USES=elfctl
-# Valid ARGS:	none
+# Usage:	USES=elfctl or USES=elfctl:ARGS
+# Valid ARGS:	build (default, implicit), stage
 #
-# Variables
+# Files listed in ELF_FEATURES are relative to:
+#   - ${BUILD_WRKSRC} when the `build` argument is supplied
+#   - ${STAGEDIR} when the `stage` argument is supplied.
 #
-#   ELF_FEATURES=	featurelist:path/to/file1 \
-#			featurelist:path/to/file1 \
-			featurelist:path/to/file2
+# Variables:
 #
-# The file paths listed in ELF_FEATURES are relative to ${BUILD_WRKSRC}.
+# ELF_FEATURES=	featurelist:path/to/file1 \
+#		featurelist:path/to/file2
 #
 
 .if !defined(_INCLUDE_USES_ELFCTL_MK)
 _INCLUDE_USES_ELFCTL_MK=	yes
 
-.  if ! empty(ELF_FEATURES)
-_USES_build+=	720:elfctl-post-build
-elfctl-post-build:
+.  if empty(elfctl_ARGS)
+elfctl_ARGS=	build
+.  endif
+
+.  if ${elfctl_ARGS} == "build"
+_ELFCTL_TOPDIR=	${BUILD_WRKSRC}
+.  elif ${elfctl_ARGS} == "stage"
+_ELFCTL_TOPDIR=	${STAGEDIR}
+.  else
+IGNORE=	USES=elfctl - invalid args: [${elfctl_ARGS}] specified
+.  endif
+
+.  if !empty(ELF_FEATURES)
+_USES_${elfctl_ARGS}+=	720:elfctl-post-${elfctl_ARGS}
+elfctl-post-${elfctl_ARGS}:
 .    for feat in ${ELF_FEATURES}
-	${ELFCTL} -i -e ${feat:C/:.*//} ${BUILD_WRKSRC}/${feat:C/.*://}
+	${ELFCTL} -i -e ${feat:C/:.*//} ${_ELFCTL_TOPDIR}/${feat:C/.*://}
 .    endfor
 .  endif