Rather than implementing support within D runtime itself, use libc
getcontext/swapcontext functions if CET is enabled.
Removes whatever CET support was in the switchContext routine for x86
D runtime, along with setting version AsmExternal, so that the fallback
ucontext_t implementation is used, which is capable of doing shadow
stack handling.
libphobos/ChangeLog:
PR d/95680
* Makefile.in: Regenerate.
* configure: Regenerate.
* configure.ac (DCFG_ENABLE_CET): Substitute.
* libdruntime/Makefile.in: Regenerate.
* libdruntime/config/x86/switchcontext.S: Remove CET support code.
* libdruntime/core/thread.d: Import gcc.config. Don't set version
AsmExternal when GNU_Enable_CET is true.
* libdruntime/gcc/config.d.in (GNU_Enable_CET): Define.
* src/Makefile.in: Regenerate.
* testsuite/Makefile.in: Regenerate.
Iain Buclaw
285d81be97