include/verbose.mk: Add sc to failure message

Add sc to build error message

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

include/verbose.mk

@@ -54,7 +54,7 @@ ifeq ($(findstring s,$(OPENWRT_VERBOSE)),)
   else
     SILENT:=>/dev/null $(if $(findstring w,$(OPENWRT_VERBOSE)),,2>&1)
     export QUIET:=1
-    SUBMAKE=cmd() { $(SILENT) $(MAKE) -s "$$@" < /dev/null || { echo "make $$*: build failed. Please re-run make with -j1 V=s to see what's going on"; false; } } 8>&1 9>&2; cmd
+    SUBMAKE=cmd() { $(SILENT) $(MAKE) -s "$$@" < /dev/null || { echo "make $$*: build failed. Please re-run make with -j1 V=s or V=sc for a higher verbosity level to see what's going on"; false; } } 8>&1 9>&2; cmd
   endif
 
   .SILENT: $(MAKECMDGOALS)