[libstdc++ PATCH] Fix leak in _Rb_tree::_M_insert (stl_tree.h)

[Earl Chew]

Gabriel Dos Reis wrote:
> Would there be a way to systematize these expclicit try-block without
> efficiency loss (a la RAII or sentry)?

Yes, RAII is preferred, but I decided to keep within the spirit of what
was already there to fix this bug rather than rewrite this and
other sections.

Earl