LINUX: Use classic major/minor macros.

Makes our Linux Audio CD code work with implementations without gnu_dev_major
and gnu_dev_minor too.

backends/audiocd/linux/linux-audiocd.cpp

@@ -62,6 +62,7 @@
 #include <linux/cdrom.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 
 enum {
 	kLeadoutTrack = 0xAA
@@ -379,8 +380,9 @@ bool LinuxAudioCDManager::tryAddDrive(DeviceList &devices, const Common::String
 
 bool LinuxAudioCDManager::tryAddDrive(DeviceList &devices, dev_t device) {
 	// Construct the block name
-	// (Does anyone have a better way to do this? bdevname is kernel only)
-	Common::String name = Common::String::format("/dev/block/%d:%d", gnu_dev_major(device), gnu_dev_minor(device));
+	// TODO: libblkid's blkid_devno_to_devname is exactly what we look for.
+	// This requires an external dependency though.
+	Common::String name = Common::String::format("/dev/block/%d:%d", major(device), minor(device));
 
 	return tryAddDrive(devices, name, device);
 }