[plplot] absolute paths to windows sdk in pc file

[Neumann-A]

Is your feature request related to a problem? Please describe.

The pc file contains absolute paths to lib sin the Windows SDK:

${prefix}/compiler/msvc/WinSDK/Windows Kits/10/Lib/10.0.26100.0/um/x64/Gdi32.Lib 
${prefix}/compiler/msvc/WinSDK/Windows Kits/10/Lib/10.0.26100.0/um/x64/ComDlg32.Lib

Proposed solution

Remove the absolute paths and just have the lib name.

Describe alternatives you've considered

No response

Additional context

No response