[ng] vala tests: avoid spurious failure with Sun C/C++ compilers

* t/vala-mix2.sh: Here, by forcing the use of the GNU C/C++ compilers.
If we don't, our dependency-tracking code forces 'make' to try to rebuild
spurious binaries or object files when the Sun C compiler is in use, with
reasons like:
  '/opt/SUNWspro/prod/include/CC/Cstd/./istream.cc' is newer \
      than target '/opt/SUNWspro/prod/include/CC/Cstd/./istream'
Go figure.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>
1 file changed