The mips arch is special in that it uses different RLIMIT_ numbers than other archs, so allow bits/resource.h to override the default RLIMIT_ numbers (empty on all archs except mips). Reported by orc. (cherry picked from commit fcea534e579077e10456f6ed06c033dfaa013a24)
the definition was found to be incorrect at least for powerpc, and fixing this cleanly requires making the definition arch-specific. this will allow cleaning up the definition for other archs to make it more specific, and reversing some of the ugliness (time_t hacks) introduced with the x32 port. this first commit simply copies the existing definition to each arch without any changes. this is intentional, to make it easier to review changes made on a per-arch basis.
this was problematic because several archs don't define __WORDSIZE. we could add it, but I would rather phase this macro out in the long term. in our version of the headers, UINTPTR_MAX is available here, so just use it instead.
introduced in linux v3.13, 62748f32d501f5d3712a7c372bbb92abc7c62bc7
most of the members should be time_t anyway, and time_t has the correct semantics for "syscall_long", so it works on all archs, even x32.
gcc -Wsign-compare warns about expanded macros that were defined in standard headers (before gcc 4.8) which can make builds fail that use -Werror. changed macros: WIFSIGNALED, __CPU_op_S
these are poorly designed (illogical argument order) and even poorly implemented (brace issues) on glibc, but unfortunately some software is using them. we could consider removing them again in the future at some point if they're documented as deprecated, but for now the simplest thing to do is just to provide them under _GNU_SOURCE.
in fixing this, I've changed the logic from ugly #if/#else blocks inside the struct shm_info definition to a fixed struct definition and optional macros to rename the elements. this will be helpful if we need to move shm_info to a bits header in the future, as it will keep the feature test logic out of bits.
the imr_, imsf_, ip6_, ip6m_, ipi_, ipi6_, SCM_, and SOL_ prefixes are not in the reserved namespace for this header. thus the constants and structures using them need to be protected under appropriate feature test macros. this also affects some headers which are permitted to include netinet/in.h, particularly netdb.h and arpa/inet.h. the SOL_ macros are moved to sys/socket.h where they are in the reserved namespace (SO*). they are still accessible via netinet/in.h since it includes sys/socket.h implicitly (which is permitted). the SCM_SRCRT macro is simply removed, since the definition used for it, IPV6_RXSRCRT is not defined anywhere. it could be re-added, this time in sys/socket.h, if the appropriate value can be determined; however, given that the erroneous definition was not caught, it is unlikely that any software actually attempts to use SCM_SRCRT.