(forwarded from ColinIanKing/fwts#5)

FWTS fails to build with the musl C library.

#warning usage of non-standard #include <sys/cdefs.h> is deprecated

That's a glibc-ism, https://wiki.musl-libc.org/faq.html recommends to use extern "C" directly.

#warning redirecting incorrect #include <sys/poll.h> to <poll.h> [-Wcpp]

Use #include <poll.h> instead. https://git.openembedded.org/meta-openembedded/tree/meta-oe/recipes-test/fwts/fwts/0001-Include-poll.h-instead-of-deprecated-sys-poll.h.patch has a patch.

fwts_uefi.c:68:35: error: '__SWORD_TYPE' undeclared (first use in this function)

This is a glibc-internal define. https://git.openembedded.org/meta-openembedded/tree/meta-oe/recipes-test/fwts/fwts/0002-Define-__SWORD_TYPE-if-not-defined-by-libc.patch has a potential fix to define it if not already defined.

libfwts.so: undefined reference to `backtrace'
libfwts.so: undefined reference to `backtrace_symbols'

These are glibc-specific. Can configure.ac check for these and disable the backtrace output? Bonus points for checking if https://www.freshports.org/devel/libexecinfo is installed as that provides an implementation for musl users. We're adding -lexecinfo to LDFLAGS to work around this one.