This introduces a new RAII class that temporarily installs an
alternate signal stack (on systems that have sigaltstack); then
changes the one gdb use of sigaltstack to use this class instead.
This will be used in a later patch, when creating new threads that may
want to handle SIGSEGV.
gdb/ChangeLog
2019-11-26 Tom Tromey <tom@tromey.com>
* main.c (setup_alternate_signal_stack): Remove.
(captured_main_1): Use gdb::alternate_signal_stack.
* gdbsupport/alt-stack.h: New file.
Change-Id: I721c047ae9d51a35fd274a6dbc00a58c6440dae6
