Update build options and include license texts
This is a small collection of updates for the SPEC file:
- git can be removed from the list of build requirements, because it is nowadays not very useful anymore.
- The build options should mirror the options that are actually available in the build system.
- All license texts should be included in the binary distribution (i.e., RPM). I'm not too happy with the naming of the library license files I chose, please let me know if you have a better idea.