Mac/Linux GHDL binary references paths from build environment

[controversial]

On the latest nightly build, ghdl-yosys-plugin references paths that only exist in the build environment:

$ ./bin/yosys -p ghdl

-- Running command `ghdl' --

1. Executing GHDL.
warning: ieee library directory '/Users/runner/work/1/s/_packages/build_darwin/fpga-toolchain/lib/ghdl/ieee/v93/' not found
error: cannot find "std" library

raised OPTIONS.OPTION_ERROR : ghdlcomp.adb:315

Ideally, the binary would be built to be portable and run in different environments

[edbordin]

This is also the case with the Linux build, see the README for how to work around this with the GHDL_PREFIX environment variable.

There was some discussion here on ways we could change the absolute prefix or make the plugin search relative to the install location as it does on windows. (cc: @tgingold @umarcor )

[controversial]

Thanks, setting GHDL_PREFIX fixes it; I hadn't seen that. Feel free to close this or to leave it open as an issue to track the more robust solution you described