Generate random BigUints and BigInts
test the correct function (oops)
Convert between BigInts and BigUints
Forgot to make accept() home for IO
Make I/O tests use run_in_mt_newsched_task to get more multi-threaded test coverage
Incorporate feedback from huonw

- use identifiers with underscores to avoid unused variable warning
- implement on R: Rng instead of on R: RngUtil
- bugfix: zero BigInts were being generated twice as often as any
  other number
- test that gen_biguint(0) always returns zero
Add with_mem_writer to std::rt::io::mem.

This is in many ways a replacement for the current
std::io::with_str_writer.
Update for_expr docs.
Fix pretty-printing of empty impl items
Convert between BigInts, BigUints, ints, and uints

Previously, conversion to ints, uints, and BigUints clamped the value
within the range of that datatype. With this commit, conversion
overflows fail the task. To handle overflows gracefully, use the new
to_*_opt() methods.
Merge RandBigUint and RandBigInt into single trait
Remove oldvisit.rs (yay!); part of #7081 refactoring.
debuginfo: Wrapped namespace facilities of llvm::DIBuilder
debuginfo: Support for namespaces (functions only)
debuginfo: Support for namespaces for types
change type of ExprLoop and ExprBreak elts from ident->name.

Lots of downstream changes in librustc, should be infinitesimally faster.
added test case
auto merge of #9103 : jbclements/rust/let-var-hygiene, r=erickt

update AST so that ExprBreak and ExprCont expressions contain names, not idents. Fixes #9047 and makes progress on #6993. Simplifies the compiler very slightly, should make it (infinitesimally) faster.
rustpkg: Pass command-line arguments to rustc

rustpkg now accepts most of rustc's command-line arguments and passes
them along to rustc when building or installing.

A few rarely-used arguments aren't implemented yet.

rustpkg doesn't support flags that don't make sense with rustpkg
(for example, --bin and --lib, which get inferred from crate file names).

Closes #8522
remove redundant tycat line from the binop table

The line marked as being for `bot` was actually for `tycat_struct`, and
can be replaced with `tycat_other`.