Build raise with -fasynchronous-unwind-tables

[Siddhesh Poyarekar]

On 24/01/20 6:03 am, Joseph Myers wrote:
> In testing glibc for Arm and MIPS, I see:
> 
> FAIL: misc/tst-sigcontext-get_pc
> 
> If this test - backtracing through a call to raise - is valid, then
> raise needs to be built with -fasynchronous-unwind-tables (as the test
> itself is) to have the required unwind information for that
> backtracing to work.  Adding that option, which this patch does,
> causes the test for pass for Arm.  For MIPS, the test still does not
> pass (the backtrace has an address that is 2 bytes after the "address
> in signal handler", for unknown reasons), although the patch allows a
> longer backtrace to be produced.
> 

The fix seems fine, but I wonder how the test passes on other
architectures.  Also the commit that introduced this test seems to
indicate that the test was passing earlier:

commit a43565ac447b1608ae2626f5012673560bb623ab
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Mon Dec 17 16:44:14 2018 -0200

    Refactor sigcontextinfo.h

Siddhesh