DTV: more helpful error if kernel headers are old

modules/access/dtv/linux.c

@@ -32,6 +32,7 @@
 #include <poll.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
+#include <linux/dvb/version.h>
 #include <linux/dvb/frontend.h>
 #include <linux/dvb/dmx.h>
 
@@ -41,6 +42,13 @@
 # define O_SEARCH O_RDONLY
 #endif
 
+#define DVBv5(minor) \
+        (DVB_API_VERSION > 5 \
+     || (DVB_API_VERSION == 5 && DVB_API_VERSION_MINOR >= (minor)))
+#if !DVBv5(0)
+# error Linux DVB kernel headers version 2.6.28 or later required.
+#endif
+
 /** Opens the device directory for the specified DVB adapter */
 static int dvb_open_adapter (uint8_t adapter)
 {