Forcing them to be embedded in makefiles precludes being able to run them in
rustbuild, and adding them to compiletest gives us a great way to leverage
future enhancements to our "all encompassing test suite runner" as well as just
moving more things into Rust.
All tests are still Makefile-based in the sense that they rely on `make` being
available to run them, but there's no longer any Makefile-trickery to run them
and rustbuild can now run them out of the box as well.
The `--disable-jemalloc` configure option has a failure mode where it will
create a distribution that is not compatible with other compilers. For example
the nightly for Linux will assume that it will link to jemalloc by default as
an allocator for executable crates. If, however, a standard library is used
which was built via `./configure --disable-jemalloc` then this will fail
because the jemalloc crate wasn't built.
While this seems somewhat reasonable as a niche situation, the same mechanism is
used for disabling jemalloc for platforms that just don't support it. For
example if the rumprun target is compiled then the sibiling Linux target *also*
doesn't have jemalloc. This is currently a problem for our cross-build nightlies
which build many targets. If rumprun is also built, it will disable jemalloc for
all targets, which isn't desired.
This commit moves the platform-specific disabling of jemalloc as hardcoded logic
into the makefiles that is scoped per-platform. This way when configuring
multiple targets **without the `--disable-jemalloc` option specified** all
targets will get jemalloc as they should.
This commit modifies the configure script and our makefiles to support building
32-bit MSVC targets. The MSVC toolchain is now parameterized over whether it can
produce a 32-bit or 64-bit binary. The configure script was updated to export
more variables at configure time, and the makefiles were rejiggered to
selectively reexport the relevant environment variables for the applicable
targets they're going to run for.
