My approach was as follows to keep it running:
gn gen out/release --args="is_debug=false target_winuwp_version=\"10\" target_cpu=\"x64\" use_rtti=true is_clang=false src_build_json=true" --ide="vs"
Change in third_party/jsoncpp/BUILD.gn edit source_set("jsoncpp") with "static_library("jsoncpp")
Change in src/rtc_base/BUILD.gn rtc_source_set("rtc_json" with "rtc_static_library("rtc_json")
Last but not least Ad LIBs
LIBS += Strmiids.lib webrtc.lib rtc_json.lib jsoncpp.lib
May this help someone else.
Cheers,
Jan-Phillip