cmake: Update paths in generated pkg-config file
cmake: Update paths in generated pkg-config file

Update paths inside the pkg-config file to respect GNUInstallDirs.

Fixes: 07805253ab5d115cb2918b4860a559967ab98bed

fukuchi/libqrencode,sballe73/libqrencode,sballe73/libqrencode,sballe73/libqrencode,sballe73/libqrencode,fukuchi/libqrencode,fukuchi/libqrencode