Use _setjmp by default to use the setjmp xor cookie.
This was already done for powerpc and powerpc64 to work around a
segfault, but it seems to be a good practice on all arches.
ok gkoehler@
clang-11's __builtin_setjmp is broken, has chance of SIGSEGV during
"make build" on powerpc with ld.lld, or when passing a wrong option
(like "ruby -e" with no -e code) on powerpc64.
ok jeremy@ (maintainer)
This comes from the Ruby fiber maintainer. It doesn't require compiling a
couple files without optimization, and it was able to get through a make
test run without crashing on sparc64, which uses the copy coroutine fiber
implementation.
OK kn@
Also add local patch to compile a couple of fiber-related
files with -O0, as that is also needed to prevent the crash
on sparc64.
Add a second distpatch to fix a regression in 2.7.2 causing
a crash when calling ffi_closure_free.
OK kn@
