Overhaul the wasm build to (A) support more coexisting variants, e.g. 32/64-bit of...

Overhaul the wasm build to (A) support more coexisting variants, e.g. 32/64-bit of both vanilla and esm, and (B) build each variant to its own subdir so that they can build in parallel. It can, with make -j4, now build all new variants in half the time it previously took for just the 32-bit builds. The new build logging output, though unconventional, serves two purposes: (A) improve my build-time situational awareness and (B) it help demystify some of the build steps and output files.

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