tce-load -i compiletc autoconf2.13 cbindgen dbus-glib-dev gtk3-dev gtk2-dev libnotify-dev node.js-dev nss-dev pulseaudio-dev startup-notification-dev zip unzip icu-dev libevent-dev libwebp-dev clang llvm-dev libXt-dev

https://archive.mozilla.org/pub/firefox/releases/68.5.0esr/source/firefox-68.5.0esr.source.tar.xz
http://www.linuxfromscratch.org/patches/blfs/9.1/firefox-68.5.0esr-system_graphite2_harfbuzz-1.patch

cd firefox-68.5.0esr

cp mozconfig ./

sed -i -e 's/Disable/Enable/' -e '/^MOZ_REQUIRE_SIGNING/s/0/1/' build/mozconfig.common

sudo ln -s /tmp/tcloop/nss-dev/usr/local/include/nss/* /usr/local/include

export CC="gcc" CXX="g++"
export MOZBUILD_STATE_PATH=${PWD}/mozbuild
./mach build

sudo ./mach install

sudo mkdir -pv  /usr/local/lib/mozilla/plugins
sudo ln -sf ../../mozilla/plugins /usr/local/lib/firefox/browser/

needs to be armv7-unknown-linux-gnueabihf for rust

edit js/src/wasm/WasmSignalHandlers.cpp

//#if defined(__linux__) && defined(__arm__)
//#  define WASM_EMULATE_ARM_UNALIGNED_FP_ACCESS
//#endif

//#ifdef WASM_EMULATE_ARM_UNALIGNED_FP_ACCESS
//#  include <sys/user.h>
//#endif

71:36.37 We know it took a while, but your build finally finished successfully!