V8 test-in-container patch

[Joseph Myers]

This appears to have broken the build for ia64.

https://sourceware.org/ml/libc-testresults/2018-q3/msg00273.html

/scratch/jmyers/glibc-bot/install/compilers/ia64-linux-gnu/lib/gcc/ia64-glibc-linux-gnu/8.2.1/../../../../ia64-glibc-linux-gnu/bin/ld: warning: libunwind.so.7, needed by /scratch/jmyers/glibc-bot/install/compilers/ia64-linux-gnu/lib/gcc/ia64-glibc-linux-gnu/8.2.1/../../../../ia64-glibc-linux-gnu/lib/libstdc++.so, not found (try using -rpath or -rpath-link)

That's linking links-dso-program (why is that being built at glibc build 
time at all anyway, rather than just when testing)?  If using -lgcc_s you 
also need to use $(libunwind).

-- 
Joseph S. Myers
joseph@codesourcery.com