Linux Gentoo with kde 4.14.1 ./configure --prefix=/usr configure: loading site script /usr/share/config.site checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking for g++... g++ checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for a BSD-compatible install... /usr/bin/install -c checking whether ln -s works... yes checking for ranlib... ranlib checking for main in -lpthread... yes checking how to run the C preprocessor... gcc -E checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking pthread.h usability... yes checking pthread.h presence... yes checking for pthread.h... yes checking for main in -lQtCore... no configure: error: *** QtCore library not installed - please install QT4 first *** pkg-config --libs-only-L QtCore -L/usr/lib64/qt4 Idea .??