qtbase examples compile failure with disabled gui module

make[2]: Leaving directory '.../build_powerpc_qt5base_failure_001/build/qt5base-5.8.0/examples/embedded'
cd gui/ && ( test -e Makefile || .../build_powerpc_qt5base_failure_001/build/qt5base-5.8.0/bin/qmake -o Makefile .../build_powerpc_qt5base_failure_001/build/qt5base-5.8.0/examples/gui/gui.pro -qtconf .../build_powerpc_qt5base_failure_001/build/qt5base-5.8.0/bin/qt.conf -- -v -prefix /usr -hostprefix .../build_powerpc_qt5base_failure_001/host/usr -headerdir /usr/include/qt5 -sysroot .../build_powerpc_qt5base_failure_001/host/usr/powerpc-buildroot-linux-uclibc/sysroot -plugindir /usr/lib/qt/plugins -examplesdir /usr/lib/qt/examples -no-rpath -nomake tests -device buildroot -device-option CROSS_COMPILE=.../build_powerpc_qt5base_failure_001/host/usr/bin/powerpc-buildroot-linux-uclibc- -device-option 'BR_COMPILER_CFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os  ' -device-option 'BR_COMPILER_CXXFLAGS=-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os  ' -optimized-qmake -no-cups -no-iconv -system-zlib -system-pcre -no-pch -shared -no-kms -release -opensource -confirm-license -no-sql-mysql -no-sql-psql -no-sql-sqlite -no-gui -no-freetype -no-widgets -no-linuxfb -no-directfb -no-xcb -no-opengl -no-eglfs -no-openssl -no-fontconfig -no-gif -no-libjpeg -no-libpng -dbus -no-tslib -no-glib -no-icu -make examples -no-libinput ) && make -f Makefile 
Project ERROR: Could not find feature opengl.
Makefile:128: recipe for target 'sub-gui-make_first' failed
make[1]: *** [sub-gui-make_first] Error 3
make[1]: Leaving directory '.../build_powerpc_qt5base_failure_001/build/qt5base-5.8.0/examples'
Makefile:71: recipe for target 'sub-examples-make_first' failed
make: *** [sub-examples-make_first] Error 2