Use a shared base image with fixed Emscripten version, autotools and optimisation flags for all C++ codecs.
Additionally, move build commands for codecs themselves to Makefile - they're already platform-specific, and Make allows for better caching and parallelisation that custom ad-hoc scripts.
This is essentially same as #777 but for C++.
It's not possible to share them across threads, so in case we decide to use multithreading in the future, it's best to mark them as thread_local right away, even if it's a no-op right now.
* Add LTO for C++ builds
This didn't have much effect on fastcomp builds, but provides further size savings with new LLVM backend we switched to in #750 (and fixes the MozJPEG size regression from the same PR).
In the future we won't need to pass `--llvm-lto 1` explicitly, but latest Emscripten Docker image doesn't contain the Emscripten version with the necessary fixes for this.
* Delete build.log
Co-authored-by: Jake Archibald <jaffathecake@gmail.com>
Looks like we've been stuck on Emscripten fastcomp backend, misssing out on all new optimisations between LLVM 6 and LLVM 11 and going via slow asm.js pipeline when building.
This changes Docker images for Emscripten projects to point to emscripten-upstream instead and commits the updated artifacts.
* Adding chroma subsampling for mozjpeg
* Adding separate chroma quality.
* Preact sometimes removes the inline styles, this fixes it.
* Simplifying chroma subsample
* Adding comments
* Switching to embind
* Adding options to mozjpeg wasm
* Updating packages
* Ditching enum - causing more problems than it's worth
* Adding mozjpeg options UI
* Forgot about this enum
* Bools just work
