Original bug report: https://bugs.gentoo.org/834450 > In file included from include/libucontext/libucontext.h:5, > from arch/ppc/makecontext.c:19: > include/libucontext/bits.h:8:9: error: unknown type name 'greg_t' > 8 | typedef greg_t libucontext_greg_t; > | ^~~~~~ In glibc 2.35: The following sys/ucontext.h files define both greg_t and gregset_t: sysdeps/arm/sys/ucontext.h sysdeps/i386/sys/ucontext.h sysdeps/m68k/sys/ucontext.h sysdeps/mips/sys/ucontext.h sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h sysdeps/unix/sysv/linux/alpha/sys/ucontext.h sysdeps/unix/sysv/linux/arm/sys/ucontext.h sysdeps/unix/sysv/linux/hppa/sys/ucontext.h sysdeps/unix/sysv/linux/m68k/sys/ucontext.h sysdeps/unix/sysv/linux/mips/sys/ucontext.h sysdeps/unix/sysv/linux/riscv/sys/ucontext.h sysdeps/unix/sysv/linux/s390/sys/ucontext.h sysdeps/unix/sysv/linux/sh/sys/ucontext.h sysdeps/unix/sysv/linux/sparc/sys/ucontext.h sysdeps/unix/sysv/linux/x86/sys/ucontext.h The following sys/ucontext.h files define gregset_t, but not greg_t: sysdeps/unix/sysv/linux/csky/sys/ucontext.h sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h The following sys/ucontext.h files do not define greg_t or gregset_t: sysdeps/generic/sys/ucontext.h sysdeps/unix/sysv/linux/arc/sys/ucontext.h sysdeps/unix/sysv/linux/ia64/sys/ucontext.h sysdeps/unix/sysv/linux/microblaze/sys/ucontext.h sysdeps/unix/sysv/linux/nios2/sys/ucontext.h sysdeps/unix/sysv/linux/or1k/sys/ucontext.h In musl, sys/ucontext.h includes ucontext.h, which includes signal.h, which includes bits/signal.h. In musl, the following bits/signal.h files define greg_t and gregset_t: arch/aarch64/bits/signal.h arch/arm/bits/signal.h arch/i386/bits/signal.h arch/m68k/bits/signal.h arch/microblaze/bits/signal.h arch/mips/bits/signal.h arch/mips64/bits/signal.h arch/mipsn32/bits/signal.h arch/or1k/bits/signal.h arch/powerpc/bits/signal.h arch/powerpc64/bits/signal.h arch/riscv64/bits/signal.h arch/s390x/bits/signal.h arch/sh/bits/signal.h arch/x32/bits/signal.h arch/x86_64/bits/signal.h In glibc, typedef for greg_t needs to be added at least in: sysdeps/unix/sysv/linux/powerpc/sys/ucontext.h (In musl, in arch/powerpc/bits/signal.h: 'typedef unsigned long greg_t, gregset_t[48]') (In musl, in arch/powerpc64/bits/signal.h: 'typedef unsigned long greg_t, gregset_t[48]') And probably also in: sysdeps/unix/sysv/linux/csky/sys/ucontext.h (Not supported by musl, but 'typedef unsigned long greg_t' seems obvious.) sysdeps/unix/sysv/linux/microblaze/sys/ucontext.h (In musl: 'typedef unsigned long greg_t, gregset_t[38]') sysdeps/unix/sysv/linux/or1k/sys/ucontext.h (In musl: 'typedef unsigned long greg_t, gregset_t[34]')
I don't think the set of definitions expected from <sys/ucontext.h> is well defined.