Relative path change

[aolofsson]

In some places like the libs and pdks, we are setting relative paths. (for historical reasons..)The current system is working, but it means it's not clear what the root is. I can guess at the root path based on knowing where the third_party is placed in the repo, but explicit is better than implicit and I don't think we should expose that part of our implementation to the user, especially now that we have the find function.

dict set sc_cfg model timing nldm typical [list ../third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/lib/NangateOpenCellLibrary_typical.lib]
dict set sc_cfg model layout lef 10M [list ../third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/lef/NangateOpenCellLibrary.macro.mod.lef]
dict set sc_cfg model layout gds 10M [list ../third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/gds/NangateOpenCellLibrary.gds]

New:

dict set sc_cfg model timing nldm typical [list third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/lib/NangateOpenCellLibrary_typical.lib]
dict set sc_cfg model layout lef 10M [list third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/lef/NangateOpenCellLibrary.macro.mod.lef]
dict set sc_cfg model layout gds 10M [list third_party/pdks/virtual/freepdk45/libs/nangate45/r1p0/gds/NangateOpenCellLibrary.gds]

[nmoroze]

We did it this way to make sure these files can be found during an editable install w/o having to set SCPATH (since the root of the Python package, aka siliconcompiler/, gets automatically added to our file search path). I don't think find_files() should be changed to somehow support just this specific case, that seems a little hacky.

An alternative could be to finally bundle the PDK data w/ the SiliconCompiler Pip package. Then these files would be under siliconcompiler/, and it might make the relative directory seem more clear in the manifest (although, they should be resolved to absolute paths in sc_manifest.tcl anyways?) This could be useful since it seems to trip people up a lot: #1068, #901, #788, #856.

I think the final long-term solution will be to package the libraries using sup :)