Buildroot-2011.08 could use both Qt3 and Qt4 for configuration menu representation depending on Qt version installed on host system.
But if there're both of them (for example Linux kernel prior 2.6.38 uses Qt3 and Qt4 I use for application development) you'll get weird error on attempt to execute graphical configuration utility of buildroot in question:
To fix this issue in Ubuntu you only need to set "moc" alternative to "moc-qt4", so /usr/bin/moc will point to "moc" from Qt4 instead of the one from Qt3 (which is set by default):
But if there're both of them (for example Linux kernel prior 2.6.38 uses Qt3 and Qt4 I use for application development) you'll get weird error on attempt to execute graphical configuration utility of buildroot in question:
$ make xconfig
mkdir -p /home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config/lxdialog
make CC="/usr/bin/gcc" HOSTCC="/usr/bin/gcc" obj=/home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config -C package/config -f Makefile.br qconf
make[1]: Entering directory `/home/_private/Downloads/buildroot-2011.08/package/config'
/usr/bin/gcc -DCURSES_LOC="<ncurses.h>" -DLOCALE -I/home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config -DQT_SHARED -DQT3_SUPPORT -I/usr/include/qt4 -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4/Qt3Support -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtSql -D LKC_DIRECT_LINK -c qconf.cc -o /home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config/qconf.o
In file included from qconf.cc:48:
/home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config/qconf.moc:13: fatal error: private/qucomextra_p.h: No such file or directory
compilation terminated.
make[1]: *** [/home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config/qconf.o] Error 1
make[1]: Leaving directory `/home/_private/Downloads/buildroot-2011.08/package/config'
make: *** [/home/_private/Downloads/buildroot-2011.08/output/build/buildroot-config/qconf] Error 2
To fix this issue in Ubuntu you only need to set "moc" alternative to "moc-qt4", so /usr/bin/moc will point to "moc" from Qt4 instead of the one from Qt3 (which is set by default):
sudo update-alternatives --config moc
There are 2 choices for the alternative moc (providing /usr/bin/moc).
Selection Path Priority Status
------------------------------------------------------------
* 0 /usr/bin/moc-qt3 45 auto mode
1 /usr/bin/moc-qt3 45 manual mode
2 /usr/bin/moc-qt4 40 manual mode
Press enter to keep the current choice[*], or type selection number: 2 
