You appear to be building some version of 3.2, not the latest as seen by the 3rd party libs tag of Tag 2020-06-30-3.2. The current build (as can be seen on the buildbot output is 2020-09-14-3.2, although updating your sources to the current version is unlikely to fix your issue.
I would suggest deleting your build directory (D:\wsbuild\326build64) and your libs directory (D:\wsbuild\wireshark-win64-libs-3.2), creating a new build dir and running the CMake generation step again.
If the generation still fails, have a look in D:\wsbuild\wireshark-win64-libs-3.2\vcpkg-export-20190318-win64ws\installed\x64-windows\bin for glib dll's.