Fix some problematic optimizations on select, GCC compatibility
Fix header generation for unsafe externals
Adds External-Unsafe for external buffers without initializer
Fix deep recursion in C++ header type reification
update pcoll to fix GCC 9 build
readme additions
Fix bad constant propagation for BitShiftLeft for Int32
clean up kc.cpp and reset ubuntu version
ubuntu.yml: mssing zlib-dev
do not override _XOPEN_SOURCE
ubuntu.yml: depend on libcurl
wasm.yml: source emsdk in build stage as well
fix ubuntu build targets
Set sr.ht build parallelism limit
Ubuntu build fixes
Fix build manifests
Binaryen backend: function import fix
Fix CMake error
Binaryen update and build fixes
merge