Readme.md doesn't have ubuntu install commands unlike other toolchains (minor issue)

[zecoxao]

it should have a line such as

apt install gcc make patch git texinfo flex bison libgsl-dev libgmp-dev libmpfr-dev libmpc-dev gettext libnewlib-dev libipt-dev babeltrace

and/or, alternatively

apt install clang make patch git texinfo flex bison libgsl-dev libgmp-dev libmpfr-dev libmpc-dev gettext libnewlib-dev libipt-dev babeltrace

the last 3 are very likely required as the config option complains about them when building the toolchain