Support for NVC simulator

[JiriG]

I have added support for the NVC simulator to grlib-gpl 2026.2. You can find the diff on github:

Added support for NVC open-source VHDL/Verilog simulator * use 'make nvc' to compile * use 'make nvc-run' to simulate

I recommend to use the latest version of NVC, built directly from the sources:

GitHub - nickg/nvc: VHDL compiler and simulator