gh-136976: Emscripten: Add _decimal and libmpdec

[hoodmane]

• Issue: Emscripten build doesn't include _decimal, _uuid, _ssl or _hashlib #136976

[hoodmane]

We'll have to merge python/buildmaster-config#615 before the buildbot will actually use this.

[freakboy3742]

+1 to the general approach (although see my comments on the buildmaster-config PR for a possible direction for minimising the need for re-builds).

However, testing this manually yielded an compilation error on the mpdec build:

wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_setminalloc.minalloc_is_set`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.1`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `stderr`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.2`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_setminalloc.minalloc_is_set`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `MPD_MINALLOC`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.1`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `stderr`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.3`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(context.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.4`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.1`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `stderr`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `.L.str.2`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_free`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_free`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_pow10`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(basearith.o): relocation R_WASM_MEMORY_ADDR_LEB cannot be used against symbol `mpd_pow10`; recompile with -fPIC wasm-ld: error: /Users/rkm/projects/python/cpython/cross-build/wasm32-emscripten/prefix/lib/libmpdec.a(convolute.o): relocation R_WASM_MEMORY_ADDR_SLEB cannot be used against symbol `mpd_moduli`; recompile with -fPIC wasm-ld: error: too many errors emitted, stopping now (use -error-limit=0 to see all errors) 

[bedevere-app]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[hoodmane]

Huh I wonder why I didn't get the fPIC problems.

[hoodmane]

I added CFLAGS=-fPIC, can you try it again?

[freakboy3742]

One minor typo, but otherwise the fPIC fix has done the job.

[miss-islington-app]

Thanks @hoodmane for the PR, and @freakboy3742 for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[bedevere-app]

GH-137066 is a backport of this pull request to the 3.14 branch.