[Bug sanitizer/57316] [4.8/4.9 regression] build failure in libsanitizer

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57316

--- Comment #12 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Yury Gribov from comment #11)
> Created attachment 31916 [details]
> More robust check
> 
> Does this look reasonable? Should also work for cross-builds.

1) these syscalls are only needed on Linux, not on Darwin I think, so you
change would disable libsanitizer on Darwin (not that I care about it)

2) I think it is undesirable to put this check into toplevel configure, I'd say
the determination when to make the whole libsanitizer UNSUPPORTED should be
limited to target triplet checking.  I think my preference would be to test
this in libsanitizer/configure* and just make even the asan etc. conditional on
an automake conditional.