Including linux kernel header files

The next release of Tellico will remove the dependency on cdparanoia’s libcdda for the CD information lookup by using an internal copy of some code from cd-discid. I didn’t want to introduce too many external dependencies. But this moves me really into the land of black magic, since I have no idea how to access CD-ROM drives.

Evidently, there’s a problem with some versions of the linux kernal or glibc header files when including linux/cdrom.h. I found more information from KDE bug #86188 and I added the same workaround to Tellico. I hope that fixes the problem in the pre-release from yesterday.