on start: "No QGIS data provider plugins found in: /usr//usr/lib64/qgis No vector layers can be loaded. Check your QGIS installation" it is fixed for me by removing the /usr in mycmakeargs to give: -D QGIS_PLUGIN_SUBDIR=$(get_libdir)/qgis qgis does seem to add the prefix: src/core/qgsapplication.cpp: setPluginPath( mPrefixPath + "/" + QString( QGIS_PLUGIN_SUBDIR ) ); I also took the /usr from QGIS_LIB_SUBDIR but is that only used for the Mac build?
Fixed. Thanks.