There was a longstanding hack that defined ucontext_t manually to work
around the lack of this header on the Android NDK. However, it looks
like newer NDK versions now have it like good little POSIX boys, and my
recent header reshuffle broke the build on those versions, presumably
because the real and fake definitions of ucontext_t end up included in
the same file where they weren't under the old organization.
Rather than try to revert the conflict, this commit just removes the
hack. The buildbot's NDK will need to be upgraded.
- Get rid of ArmMemTools.cpp and rename x64MemTools.cpp to MemTools.cpp.
ArmMemTools was almost identical to the POSIX part of x64MemTools, and
the two differences, (a) lack of sigaltstack, which I added to the
latter recently, and (b) use of r10 to determine the fault address
instead of info->si_addr (meaning it only works for specifically
formatted JIT code), I don't think are necessary. (Plus Android, see
below.)
- Rename Core/PowerPC/JitCommon/JitBackpatch.h to Core/MachineContext.h.
It doesn't contain anything JIT-specific anymore, and e.g. locking
will want to use faulting support regardless of whether any JIT is in
use.
- Get rid of different definitions of SContext for different
architectures under __linux__, since this is POSIX. The exception is
of course Android being shitty; I moved the workaround definition from
ArmMemTools.cpp to here.
- Get rid of #ifdefs around EMM::InstallExceptionHandler and just
provide an empty implementation for unsupported systems (i.e.
_M_GENERIC really). Added const bool g_exception_handlers_supported
for future use; currently exception handlers are only used by the JIT,
whose use implies non-M_GENERIC, but locking will change that.
- Remove an unnecessary typedef.
