Error during installation of INTL extension

Hello,
I’m trying to install the INTL extension on Local. I’m following the tutorial “How do I compile additional PHP extensions?” but when I try thi command apt-get install -y build-essential autoconf pkg-config the answer is
Reading package lists… Done
Building dependency tree
Reading state information… Done
Package pkg-config is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

Package build-essential is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package ‘build-essential’ has no installation candidate
E: Unable to locate package autoconf
E: Package ‘pkg-config’ has no installation candidate

Please could anyone help me ?
Thank you very much
Rob

Hey @pigrecolab

Can you provide the complete terminal output? I’m wondering if the apt-get update command finished successfully.