flac: add --disable-thorough-tests and fix licenses.
flac: add --disable-thorough-tests and fix licenses.

Without tests take very long, also take the opportunity to
fix xlint errors.

Closes: #9401 [via git-merge-pr]

coredumb/void-packages,necrophcodr/void-packages,NeoChontrix/void-packages,floGik/void-packages,necrophcodr/void-packages,coredumb/void-packages,necrophcodr/void-packages,floGik/void-packages,NeoChontrix/void-packages,floGik/void-packages,coredumb/void-packages,coredumb/void-packages,necrophcodr/void-packages,floGik/void-packages,NeoChontrix/void-packages,NeoChontrix/void-packages,coredumb/void-packages,NeoChontrix/void-packages,floGik/void-packages,NeoChontrix/void-packages,coredumb/void-packages,necrophcodr/void-packages,floGik/void-packages