Zephyr Workbench, a VSCode extension to manage Zephyr on STM32.
It enables users to easily create, develop, and debug Zephyr applications.
Main features:
Install host dependencies.
Import toolchain and SDK.
Create, configure, build and manage apps.
Debug STM32.
You can directly download it from the VSCode marketplace
For more details, visit the Zephyr Workbench
There were no gnu99 or gnu11 in the MCU GCC Compiler -> Dialect -> Language Standard combo-box, so I had to write -std=gnu99 in the Other dialect flags field which did the job.