https://bugzilla.redhat.com/show_bug.cgi?id=1809261
--- Comment #2 from Damian Wrobel dwrobel@ertelnet.rybnik.pl --- (In reply to Artur Iwicki from comment #1)
Use the %set_build_flags macro instead.
Done.
You should extract the licence from the file, e.g. using awk or head.
I would prefer not to generate the license file, if possible. So, I contacted upstream to consider to include a separate license text file [1].
[1] https://sourceforge.net/p/fixedptc/code/merge-requests/2/