Further and clearer error when extern C missing

[GiuseppeSorrentino99]

Hello,
I am writing the issue to highlight that when the extern C keyword is missing in the cpp file read through the Kernel Object, the error looks like this:

cp: cannot stat '/mnt/c/.../AppData/Local/Temp/pnxn0lqj0kd/build_template/final.xclbin': No such file or directory

When debugging options are enabled, the error looks like a mlir compile error, with issues on the kernel name.
A clearer message error would simplify the debugging phase since everything is solved by just adding the extern C correctly to the cpp file.
Thanks