fix kernel version detection in switch driver

git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@2782 3c298f89-4303-0410-b956-a3cf2f4a3e73

target/linux/package/switch/src/Makefile

@@ -11,8 +11,9 @@
 #
 
 obj-m	:= switch-core.o switch-adm.o switch-robo.o
-export-objs := switch-core.o
 
 ifeq ($(MAKING_MODULES),1)
+export-objs := switch-core.o
+
 -include $(TOPDIR)/Rules.make
 endif

target/linux/package/switch/src/switch-core.h

@@ -1,6 +1,7 @@
 #ifndef __SWITCH_CORE_H
 #define __SWITCH_CORE_H
 
+#include <linux/version.h>
 #include <linux/list.h>
 #define SWITCH_MAX_BUFSZ	4096
 
@@ -8,6 +9,14 @@
 #define SWITCH_MEDIA_100	2
 #define SWITCH_MEDIA_FD		4
 
+#ifndef KERNEL_VERSION
+#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))
+#endif
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
+#define LINUX_2_4
+#endif
+
 typedef int (*switch_handler)(char *buf, int nr);
 
 typedef struct {