Add support for Linux 3.x and newer

git-svn-id: http://madwifi-project.org/svn/madwifi/trunk@4143 0192ed92-7a03-0410-a25b-9323aeb14dbd

Makefile

@@ -170,13 +170,15 @@ unload:
 configcheck: sanitycheck
 	@echo -n "Checking kernel configuration... "
 	
-	@# check version of kernel
-	@echo $(KERNELRELEASE) | grep -q -i '^[2-9]\.[4-9]\.' || { \
-	    echo "FAILED"; \
+	@# check kernel version
+	@case $(KERNELRELEASE) in \
+	    2.[456].*) ;; \
+	    [3-9].*) ;; \
+	    *) echo "FAILED"; \
 	       echo "Only kernel versions 2.4.x and above are supported."; \
 	       echo "You have $(KERNELRELEASE)."; \
-	    exit 1; \
-	}
+	       exit 1 ;; \
+	esac
 	
 	@# check kernel configuration
 	@if [ -z "$(CONFIG_SYSCTL)" ]; then \