Make dump_ranger routines externally visible.
There was an inline extern declaration for dump_ranger that was a bit of
a hack. I've removed it in favor of an actual prototype. There are
also some trivial changes to the dumping code in the path solver.
gcc/ChangeLog:
* gimple-range-path.cc (path_range_query::path_range_query): Add
header.
(path_range_query::dump): Remove extern declaration of dump_ranger.
* gimple-range-trace.cc (dump_ranger): Add DEBUG_FUNCTION marker.
* gimple-range-trace.h (dump_ranger): Add prototype.