Hi,

I am trying to add support for the musl toolchain to FFmpeg.

FFmpeg needs support for library features defined in POSIX.1-2001 with XSI extension and the standards below. Currently configure probes the host and target libc by checking for defined macros like __GLIBC__ and __UCLIBC__. In case of glibc and uclibc it sets -D_XOPEN_SOURCE=600 properly.

After this it checks for some combinations of hardware and the probed libc to set some more compile options, if necessary.

I know that musl does not have a macro __MUSL__ and I have read the explanation. However, I don't understand what's meant by "[..] it's a bug to assume a certain implementation has particular properties rather than testing." and how does it affect the way FFmpeg probes for the libc.

What could be a solution which supports musl?

Many thanks!
Jörg