xz: update to 5.1.2alpha to match FC18

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
xz-toolfile: add $XZ_BASE/bin to PATH

xz package build standard utilities, thus we should use them
instead from the system.

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
valgrind: update to r13418

Signed-off-by: David Abdurachmanov <davidlt@cern.ch>
gdb: disable rpath, enable xz and pcre

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