frontier_client: add CXXFLAGS to install step

On install step Makefile does final linking step, thus need to pass
identical CXXFLAGS. We should check if Makefile supports LDFLAGS.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
pythia6-toolfile: make pydata available for SLC*/FC*

pydata was limited to SLC* Linux distributions and GCC version.
Remove GCC version limitation and make it available for SLC and
FC (Fedora) distributions, i.e. for Linux.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>