Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
In my case (Ubuntu 14, 64bit) the fix was to install some 32-bit libraries.
The error is misleading, it's actually dependencies of the (32-bit) arm gcc binary not being found.