diff --git a/cfg.mk b/cfg.mk
index 71e9a1d901..b517e7ccb2 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -592,7 +592,7 @@ sc_libvirt_unmarked_diagnostics:
 	  $(_sc_search_regexp)
 	@{ grep     -nE '\<$(func_re) *\(.*;$$' $$($(VC_LIST_EXCEPT));   \
 	   grep -A1 -nE '\<$(func_re) *\(.*,$$' $$($(VC_LIST_EXCEPT)); } \
-	   | sed 's/_("[^"][^"]*"//;s/[	 ]"%s"//'			\
+	   | sed 's/_("\([^\"]\|\\.\)\+"//;s/[	 ]"%s"//'		\
 	   | grep '[	 ]"' &&						\
 	  { echo '$(ME): found unmarked diagnostic(s)' 1>&2;		\
 	    exit 1; } || :