Getting Apple's libstdc++ debug mode into the FSF tree

[Gabriel Dos Reis]

Doug Gregor <dgregor@apple.com> writes:

| Matt was asking about precedent w.r.t. linking against different
| libraries based on a macro, and it sounds like -pthreads is it. So in
| the next revision of the patch I'll make _GLIBCXX_DEBUG an
| implementation detail, and use a formal switch that will (a) define
| _GLIBCXX_DEBUG and (b) link against the debug library. Here are some
| options for the name of the formal switch:
| 
| 	-lstdc++-debug) Gaby's suggestion
| 	-debug or -debug=c++) Benjamin's comment

Actually I meant what Benjamin suggested, i.e. -debug=c++.

(The comment on "when asked tp add -lstdc++-debug" should read 
"when a compiler flag activates -lstdc++-debug")

-- Gaby