Bug#806292: nss FTCBFS: mixes build arch and host arch objects while linking in external_tests

[Helmut Grohne]

Source: nss
Version: 3.21-1
User: helmutg at debian.org
Usertags: rebootstrap

Hi Mike,

After your 3.21-1 upload the rebootstrap qa tool ran into trouble
cross building nss (which worked just fine earlier). You can find an
example failure at:
https://jenkins.debian.net/job/rebootstrap_ppc64_gcc5/79/console

With your help, we already understand some aspects of the issue:

 * external_tests was added in 3.21.
 * According to the README it is supposed to be disabled.
 * It mixes build arch and host arch cross toolchains.
 * Likely this is due to CCC not being passed into the build.
 * It should be possible to disable those tests by setting
   NSS_DISABLE_GTESTS
 * The external_tests appear to not be installed into the package and
   neither be run

I am testing cross builds with setting NSS_DISABLE_GTESTS=1 and with
setting CCC=$(CXX) now.

Thank you very much for your support

Helmut