This is necessary in order to be consistent with the following comment
in the definition of _Unwind_RaiseException() in the GCC source file
libgcc/unwind-seh.c:
The exception handler installed in crt0 will continue any GCC
exception that reaches there (and isn't marked non-continuable).
Previously we failed to do this and, as a consequence, the C++ runtime
didn't call std::terminate after an unhandled exception.
This fixes the problem reported here:
https://cygwin.com/pipermail/cygwin/2019-October/242795.htmlhttps://sourceware.org/pipermail/cygwin/2020-August/245897.html
If the acl_t struct was at or above 0x80000000 then the pointer was
sign-extended to 0xffff_ffff_8000_0000 and so the index was lost.
Signed-off-by: David Allsopp <david.allsopp@metastack.com>