and rust_exit_task_glue calls the rust main.

This is simpler since we only need to setup one frame. It also matches
what ld.so does, so gdb is happy and stops a backtrace at rust_exit_task_glue
instead of continuing past whatever function happened to be before
rust_exit_task_glue is the object file.

This is the rt part and should be merged after the rust0 part.

and rust_exit_task_glue calls the rust main.

This is simpler since we only need to setup one frame. It also matches
what ld.so does, so gdb is happy and stops a backtrace at rust_exit_task_glue
instead of continuing past whatever function happened to be before
rust_exit_task_glue is the object file.

This is only the rustc changes and should be merged first.

as well as a test case

This commit reinstates the requirement that the predicate in a
"check" must be a manifest call to a special kind of function
declared with the new "pred" keyword instead of "fn". Preds must
have a boolean return type and can only call other preds; they
can't have any effects (as enforced by the typechecker).
The arguments to a predicate in a check expression must be
slot variables or literals.

Also added the --batch flag to texi2pdf, as it doesn't really ever
seem useful to drop to the TeX prompt during a build.

Check that the operand in a constraint is an explicit name,
and that the operands are all local variables or literals. Still need
to check that the name refers to a pure function.

In addition, fix bug in fold that was turning asserts into checks.

More typechecking still needs to be done.

This should make compilation a bit less noisy.

This ensures we don't get compile errors on unreachable code (see
test/run-pass/artificial-block.rs for an example of sane code that
wasn't compiling). In the future, we might want to warn about
non-trivial code appearing in an unreachable context, and/or avoid
generating unreachable code altogether (though I'm sure LLVM will weed
it out as well).

The pass now uses walk.

Since moving to a downloadable snapshot for stage0, it's been
possible to complete the build without compiling code written
in ocaml. However, the configure script still required it to
be present.

This commit changes detection failure to a non-fatal condition,
allowing the build to complete on systems without an ocaml
compiler.

An info message is also made conditional.

This applies c11675 by Julian Seward from valgrind trunk
(svn://svn.valgrind.org/valgrind/trunk) to rustrt's included
copies of memcheck.h and valgrind.h, effectively backporting
the fix from the unreleased 3.6.2. The commit simply applies
the gcc 'unused' attribute to the relevant declarations.

This change allows compilation of the runtime code under
gcc 4.6 with -Werror, as the makefile currently requests.