This appears to have caused performance regressions, which will need to be investigated.
This reverts commit 0b0284ba21989a0b8377f0a4d1057e3e7cd5fae1.
This reverts commit 4bde728b0eb8d277c8f59bfaf24869da67c68c47.
...via moving it all to linux-only. Clang is picky about flags, and the osx
linker doesn't accept -z flags. Technically, this will likely break
clang-on-linux, but that's not a config that we run and I'll probably end up
fixing it later.
This makes us fully position independant and have a noexec stack. There's a
small chance that the former part of that can interfere with
gdb/corefiles/stackdumps, but we'll handle that if it becomes a problem.
A.J. Beamon