We currently use a 32-bit Rust toolchain for win32 builds, but this can lead
to OOM situations. This patch makes win32 builds use a 64-bit Rust toolchain,
which requires a little bit of extra configuration because rustc needs to
be able to find a link.exe that produces 64-bit binaries for building
things like build scripts, which are host binaries.
We will now generate a batch file that sets LIB to the paths to 64-bit
libraries and invokes the x64-targeting link.exe, and add a section to the
.cargo/config file to instruct cargo to use that batch file as the linker
when producing 64-bit binaries.
MozReview-Commit-ID: 9vKBbm7Gvra
--HG--
extra : rebase_source : 599b3b661c7a8a5db1f32a2a9732fc202fb55e1e
The new VS package is now based on update 15.4.2, although that release didn't affect any files in our package. I'm picking up the update mostly just to make filename unique.