Small improvements around 'size versioning' and TargetDesc (#2325)
Small improvements around 'size versioning' and TargetDesc (#2325)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Small improvement around struct size versioning with TargetDesc.

* Small improvements around handling structure size.

* Check the structureSize field is the first field.

* Work around some issues with gcc and SLANG_OFFSET_OF.
shader-slang/slang,shader-slang/slang,csyonghe/slang,shader-slang/slang,csyonghe/slang,csyonghe/slang