[Bug ada/82141] [8 Regression] raised RTSFIND.RE_NOT_AVAILABLE : rtsfind.adb:851 on darwin

[simon at pushface dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82141

--- Comment #28 from simon at pushface dot org ---
(In reply to Iain Sandoe from comment #23)

> --with-checking=release --disable-libada succeeds for me too.

Because the bug appears when building libada. I haven’t tried with 
--checking=release.

I get identical failures on Darwin 15 and Darwin 16.

For the Darwin 15 build (+ patch to darwin.h from PR80556) was 
configured with

--prefix=/Volumes/Miscellaneous/tmp/opt/gcc-8.0.0 
--without-libiconv-prefix 
--disable-libmudflap 
--disable-libstdcxx-pch 
--disable-libsanitizer 
--disable-libcc1 
--disable-libcilkrts 
--disable-multilib 
--disable-nls 
--enable-languages=c,c++,ada 
--build=x86_64-apple-darwin15

and built with make -k; these components all showed the RTSFIND 
error:

g-exptty
g-locfil
s-gloloc
g-socthi

I tried removing these from the build, to see whether the exception 
problem showed up in simpler code, but s-gloloc is used indirectly 
by rtsfind, so I stopped.

The fix in PR80556 is to do with getting a sane unwinder; if left out 
(and not overriding the default ldflags (-static-libccc, 
-static-libstdc++)), any exception results in a SEGV (and *not* on
the same components! g-exptty, g-mbdira, s-imenne, g-socthi)

I wonder whether the check-acats exception issues in PR81361 are 
related?

BTW, I’ve only used the --disable-libada etc. approach when building
a cross-compiler.