Commands to reproduce:

tar -xzf qt-everywhere-opensource-src-5.6.0.tar.gz
cd qt-everywhere-opensource-src-5.6.0/
./configure -confirm-license -no-compile-examples -opensource -qt-xcb -static
gmake

gmake fails with:

...
g++ -c -pipe -O2 -std=gnu++0x -fno-exceptions -Wall -W -D_REENTRANT -fPIC -DQT_NO_MTDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_SERIALBUS_LIB -DQT_NETWORK_LIB -DQT_SERIALPORT_LIB -DQT_CORE_LIB -I. -I. -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtWidgets -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtGui -I../../../../include/QtSerialBus/5.6.0 -I../../../../include/QtSerialBus/5.6.0/QtSerialBus -I../../../../include -I../../../../include/QtSerialBus -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtNetwork -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include/QtSerialPort -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0 -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0/QtCore -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore -I.moc -isystem /usr/include/libdrm -I.uic -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/mkspecs/linux-g++ -o .obj/moc_plaintextedit.o .moc/moc_plaintextedit.cpp
/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/bin/moc -DQT_NO_MTDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_SERIALBUS_LIB -DQT_NETWORK_LIB -DQT_SERIALPORT_LIB -DQT_CORE_LIB -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/mkspecs/linux-g++ -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples/serialbus/modbus/adueditor -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples/serialbus/modbus/adueditor -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtWidgets -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtGui -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/include/QtSerialBus/5.6.0 -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/include/QtSerialBus/5.6.0/QtSerialBus -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/include/QtSerialBus -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtNetwork -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include/QtSerialPort -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0 -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0/QtCore -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore -I/app/devel/inc -I/app/devel/h -I/app/devel/inc/RGSLibApp -I/app/devel/h/MariaDB -I/app/devel/h/PostgreSQL -I/app/devel/h/Qt5 -I/app/devel/h/Readline -I/app/devel/h/RGSLibApp -I/usr/include/c++/4.9.2 -I/usr/include/c++/4.9.2/x86_64-mageia-linux-gnu -I/usr/include/c++/4.9.2/backward -I/usr/lib/gcc/x86_64-mageia-linux-gnu/4.9.2/include -I/usr/local/include -I/usr/include modbustcpclient.h -o .moc/moc_modbustcpclient.cpp
g++ -c -pipe -O2 -std=gnu++0x -fno-exceptions -Wall -W -D_REENTRANT -fPIC -DQT_NO_MTDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_SERIALBUS_LIB -DQT_NETWORK_LIB -DQT_SERIALPORT_LIB -DQT_CORE_LIB -I. -I. -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtWidgets -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtGui -I../../../../include/QtSerialBus/5.6.0 -I../../../../include/QtSerialBus/5.6.0/QtSerialBus -I../../../../include -I../../../../include/QtSerialBus -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtNetwork -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/include/QtSerialPort -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0 -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore/5.6.0/QtCore -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/include/QtCore -I.moc -isystem /usr/include/libdrm -I.uic -I/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/mkspecs/linux-g++ -o .obj/moc_modbustcpclient.o .moc/moc_modbustcpclient.cpp
g++ -Wl,-O1 -fuse-ld=gold -Wl,--enable-new-dtags -o adueditor .obj/main.o .obj/mainwindow.o .obj/modbustcpclient.o .obj/adueditor_plugin_import.o .obj/moc_mainwindow.o .obj/moc_plaintextedit.o .obj/moc_modbustcpclient.o   -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/lib -lQt5Widgets -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/lib -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialport/lib -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/plugins/platforms -lqxcb -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/src/plugins/platforms/xcb/xcb-static -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/plugins/xcbglintegrations -lqxcb-egl-integration -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/src/plugins/platforms/xcb/gl_integrations/xcb_egl/xcb-static -lqxcb-glx-integration -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/src/plugins/platforms/xcb/gl_integrations/xcb_glx/xcb-static -lQt5XcbQpa -lXi -lSM -lICE -lxcb-static -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtimageformats/plugins/imageformats -lqdds -lqicns -lqtga -lqtiff -lqwbmp -lqwebp -lwebp -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/plugins/imageformats -lqico -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/plugins/egldeviceintegrations -lqeglfs-kms-integration -ldrm -lgbm -lqeglfs-x11-integration -lX11-xcb -lxcb -lQt5EglDeviceIntegration -lQt5PlatformSupport -lfontconfig -lfreetype -lXrender -lXext -lX11 -lQt5Gui -ljpeg -lpng -lqtharfbuzzng -lEGL -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/plugins/canbus -lqtpeakcanbus -lqtsocketcanbus -lqttinycanbus -lQt5SerialBus -lQt5SerialPort -ludev -L/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtbase/plugins/bearer -lqconnmanbearer -lqgenericbearer -lqnmbearer -lQt5Network -lQt5DBus -ldbus-1 -lQt5Core -lz -licui18n -licuuc -licudata -lpcre16 -lm -ldl -lgthread-2.0 -pthread -lglib-2.0 -lrt -lGL -lpthread 
/bin/ld.gold: error: /storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/lib/libQt5SerialBus.a(qmodbusdevice.o): multiple definition of 'QT_MODBUS()'
/bin/ld.gold: .obj/mainwindow.o: previous definition here
/bin/ld.gold: error: /storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/lib/libQt5SerialBus.a(qmodbusdevice.o): multiple definition of 'QT_MODBUS_LOW()'
/bin/ld.gold: .obj/mainwindow.o: previous definition here
collect2: error: ld returned 1 exit status
Makefile:91: recipe for target 'adueditor' failed
gmake[5]: *** [adueditor] Error 1
gmake[5]: Leaving directory '/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples/serialbus/modbus/adueditor'
Makefile:94: recipe for target 'sub-adueditor-make_first' failed
gmake[4]: *** [sub-adueditor-make_first] Error 2
gmake[4]: Leaving directory '/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples/serialbus/modbus'
Makefile:68: recipe for target 'sub-modbus-make_first' failed
gmake[3]: *** [sub-modbus-make_first] Error 2
gmake[3]: Leaving directory '/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples/serialbus'
Makefile:42: recipe for target 'sub-serialbus-make_first' failed
gmake[2]: *** [sub-serialbus-make_first] Error 2
gmake[2]: Leaving directory '/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus/examples'
Makefile:69: recipe for target 'sub-examples-make_first' failed
gmake[1]: *** [sub-examples-make_first] Error 2
gmake[1]: Leaving directory '/storage/RGSPackager/Qt5/build/qt-everywhere-opensource-src-5.6.0/qtserialbus'
Makefile:222: recipe for target 'module-qtserialbus-make_first' failed
gmake: *** [module-qtserialbus-make_first] Error 2