diff --git a/share/mk/bsd.symver.mk b/share/mk/bsd.symver.mk
index 40c51a42578a..3debc695d5a9 100644
--- a/share/mk/bsd.symver.mk
+++ b/share/mk/bsd.symver.mk
@@ -35,8 +35,10 @@ _vgen=  ${path}/${VERSION_GEN}
 .endif
 .endfor
 
+# Run the symbol maps through the C preprocessor before passing
+# them to the symbol version generator.
 ${VERSION_MAP}: ${VERSION_DEF} ${_vgen} ${SYMBOL_MAPS}
-	awk -v vfile=${VERSION_DEF} -f ${_vgen} ${SYMBOL_MAPS} \
-	    > ${.TARGET}
+	cat ${SYMBOL_MAPS} | ${CPP} - - \
+	    | awk -v vfile=${VERSION_DEF} -f ${_vgen} > ${.TARGET}
 .endif	# !empty(VERSION_DEF) && !empty(SYMBOL_MAPS)
 .endif  # !target(__<bsd.symver.mk>__)