My signond is installed to a custom location (jhbuild) and so I hit this error when trying to build signon-ui:
g++ -c -pipe -fno-exceptions -fno-rtti -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -O2 -D_REENTRANT -pthread -Wall -W -DDEBUG_ENABLED -DI18N_DOMAIN=\"signon-ui\" -DQT_NO_DEBUG -DQT_WEBKIT_LIB -DQT_DBUS_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/lib64/qt4/mkspecs/linux-g++ -I. -I/usr/include/QtCore -I/usr/include/QtNetwork -I/usr/include/QtGui -I/usr/include/QtDBus -I/usr/include/QtWebKit -I/usr/include -I. -I/usr/include/accounts-qt -I/usr/include/QtXml -I/usr/include/signon-plugins -I/usr/include/signon-plugins/SignOn -I../../../../usr/include/glib-2.0 -I../../../../usr/lib64/glib-2.0/include -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng15 -I../../../../usr/include/signon-qt -I../../../../usr/include/signon-qt/SignOn -o browser-request.o browser-request.cpp
browser-request.cpp:40:39: fatal error: SignOn/uisessiondata_priv.h: No such file or directory
Adding 'signon-plugins' to PKGCONFIG to src/src.pro seems to fix this.