plplay: add -s software decoding option and window impl selection

Any reason not to use <getopt.h>?

resolved all threads

added 26 commits

• 0fa4125a...2eaf1d68 - 23 commits from branch videolan:master
• 76edbcce - plplay: add more flexible arg parsing
• 92db71aa - plplay: add -s software decoding option
• cc2d043a - plplay: add window impl selection

Compare with previous version

approved this merge request

enabled an automatic merge when the pipeline for cc2d043a succeeds

changed milestone to %v6.283+

merged