Stop using C++ exceptions for stack unwinding.
auto merge of #11121 : vadimcn/rust/no-c++2, r=alexcrichton

This PR removes Rust's dependency on C++ for exception handling. Instead, it will use the unwind library API directly.

closes #10469
Remove rust_globals.h
auto merge of #10961 : brson/rust/lessc, r=alexcrichton
std: uniform modules titles for doc

This commit uniforms the short title of modules provided by libstd,
in order to make their roles more explicit when glancing at the index.

Signed-off-by: Luca Bruno <lucab@debian.org>