gdb/remote: don't error if qGetTIBAddr is unsupported

This change makes it possible to debug PE executables run in e.g. Qemu
without needing to set osabi to none, it breaks backtrace
and commands like finish if frame pointers are not present but SEH unwind info is.

Approved-By: Tom Tromey <tom@tromey.com>
1 file changed