Cannot find "/usr/bin/arm-none-eabi-gcc"

I realize that this is a simple question, but with a not so simple answer.

Since a few weeks I'm using the vscode flatpak. I need to build my software with a cross compiler, mostly `arm-none-eabi-gcc`. It is installed on my system, but from with vscode it cannot be found. So, my question:
How can I enable `/usr/bin/arm-none-eabi-gcc` and friends from vscode?