PR 953
* elaborate.h (derived_probe): Add field "name". Stop passing
"probe index" to other emit_* calls.
(emit_probe_context_vars): New member function.
* elaborate.cxx (derived_probe ctor): Generate unique name.
* translate.cxx (*): Adapt to index->name.
(emit_probe): Realize that probe locals only occur at nesting=0.
* tapsets.cxx (*derived_probe::emit_*): Adapt to index->name.
(mark_var_expanding_copy_visitor): New class to process $argN.
(mark_derived_probe ctor): Call it.
(mark_derived_probe::emit_probe_context_vars): Do it.
* buildrun.cxx (compile_pass): Add more optional gcc verbosity.
Add CFLAGS += -freorder-blocks.
* testsuite/buildok/marker.stp: New test.