Add support for RISCV{32,64} to glibc bindings

[ibuclaw]

Tested on riscv-qemu.

function qemu_risv {
  ~/riscv-qemu/build/./riscv64-linux-user/qemu-riscv64 \
    -L /usr/riscv64-linux-gnu \
    -E LD_LIBRARY_PATH=~/gdc/riscv/riscv64-linux-gnu/libgcc $@;
}

for test in $(qemu_risv ./unittest_static); do
  qemu_risv ./unittest_static $test;
done

0.010s PASS release64 core.atomic
0.001s PASS release64 core.bitop
0.001s PASS release64 core.checkedint
0.129s PASS release64 core.demangle
0.002s PASS release64 core.exception
0.031s PASS release64 core.internal.arrayop
0.000s PASS release64 core.internal.hash
0.002s PASS release64 core.internal.parseoptions
0.001s PASS release64 core.internal.string
0.000s PASS release64 core.math
0.004s PASS release64 core.memory
0.000s PASS release64 core.stdc.stdlib
0.027s PASS release64 core.sync.barrier
0.044s PASS release64 core.sync.condition
0.000s PASS release64 core.sync.config
0.028s PASS release64 core.sync.mutex
0.019s PASS release64 core.sync.rwmutex
0.027s PASS release64 core.sync.semaphore
0.258s PASS release64 core.thread
0.105s PASS release64 core.time
0.005s PASS release64 gcc.backtrace
0.024s PASS release64 object
0.003s PASS release64 rt.aApply
0.003s PASS release64 rt.aApplyR
0.002s PASS release64 rt.aaA
0.000s PASS release64 rt.adi
0.000s PASS release64 rt.arrayassign
0.000s PASS release64 rt.arraycast
0.015s PASS release64 rt.lifetime
0.009s PASS release64 rt.minfo
0.000s PASS release64 rt.monitor_
0.000s PASS release64 rt.qsort
0.000s PASS release64 rt.typeinfo.ti_Aint
0.004s PASS release64 rt.util.container.array
0.008s PASS release64 rt.util.container.hashtab
0.438s PASS release64 rt.util.container.treap
0.008s PASS release64 rt.util.utf
0.000s PASS release64 gc.bits
0.436s PASS release64 gc.impl.conservative.gc
0.000s PASS release64 gc.pooltable
0.001s PASS release64 core.sys.posix.stdio
0.000s PASS release64 core.sys.posix.sys.select
0.001s PASS release64 core.sys.linux.stdio
0.000s PASS release64 core.sys.linux.tipc

[dlang-bot]

Thanks for your pull request, @ibuclaw!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + druntime#2355"

[ibuclaw]

Fixed up src/core/sys/posix/sys/msg.d, as there is a difference between RISCV32 and RISCV64. However it is the same difference as other targets that mirror the generic libc headers. The different should be D_LP64 instead, which is a potential refactoring.

[thewilsonator]

Please rebase.

[ibuclaw]

Rebased.

[thewilsonator]

Thanks.

[ibuclaw]

@TurkeyMan - First user of __traits(getTargetInfo) ! (ABI models of RISC-V are "soft", "single", "double", and "quad" https://github.com/riscv/riscv-c-api-doc/blob/master/riscv-c-api.md#preprocessor-definitions :-)

[TurkeyMan]

Yay! We should support basically everything we can behind getTargetInfo! It's a nice clean tidy and centralised way to get at target info!