qemu/configs/meson/emscripten.txt

[built-in options]
c_args = ['-pthread']
cpp_args = ['-pthread']
objc_args = ['-pthread']
# -sPROXY_TO_PTHREAD link time flag always requires -pthread even during
# configuration so explicitly add the flag here.
c_link_args = ['-pthread','-sASYNCIFY=1','-sPROXY_TO_PTHREAD=1','-sFORCE_FILESYSTEM','-sALLOW_TABLE_GROWTH','-sTOTAL_MEMORY=2GB','-sWASM_BIGINT','-sEXPORT_ES6=1','-sASYNCIFY_IMPORTS=ffi_call_js','-sEXPORTED_RUNTIME_METHODS=addFunction,removeFunction,TTY,FS']
cpp_link_args = ['-pthread','-sASYNCIFY=1','-sPROXY_TO_PTHREAD=1','-sFORCE_FILESYSTEM','-sALLOW_TABLE_GROWTH','-sTOTAL_MEMORY=2GB','-sWASM_BIGINT','-sEXPORT_ES6=1','-sASYNCIFY_IMPORTS=ffi_call_js','-sEXPORTED_RUNTIME_METHODS=addFunction,removeFunction,TTY,FS']