Libunwind provides a sigreturn stub for x86 in version 1.2 [1]. However the arch still depends on setcontext() which is unavailable in musl-libc and which is supposed to be "deprecated everywhere" [2] [1] x86 sigreturn unimplemented for some libcs, https://github.com/libunwind/libunwind/issues/13 [2] setcontext deprecated on x86, https://github.com/libunwind/libunwind/issues/69 Refs: https://github.com/openwrt/packages/issues/8548#issuecomment-497791552 Reported-by: Rosen Penev <rosenp@gmail.com> Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>