... so it fails if these aren't available; instead use the
C++ compiler of the LO build system.

Change-Id: I8a95d1865c481dc0a790d6fec6ff9fae8284d76d
Reviewed-on: https://gerrit.libreoffice.org/67078Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Jenkins