Fix the list of libraries expended in the pc file

[vaplv]

Modifies the private dependency string created from CMake targets to ensure that the names of the libraries listed in the generated pc file are not CMake-defined target names. They must correctly refer to the libraries on disk, as expected by the "-l" link option.

Note that this issue appears to be recurring and occurs frequently, in fact every time CMake targets change their naming convention.

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