add config symbols for the kernel version

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@9520 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 4 insertions, 0 deletions

diff --git a/rules.mk b/rules.mk
index 5c66dfde1..4a0fa32e3 100644
--- a/rules.mk
+++ b/rules.mk
@@ -138,6 +138,10 @@ $(call shvar,$(1))=$$(call $(1))
 export $(call shvar,$(1))
 endef
 
+define confvar
+$(foreach v,$(1),$(if $($(v)),y,n))
+endef
+
 # file extension
 ext=$(word $(words $(subst ., ,$(1))),$(subst ., ,$(1)))