When emerging gcc-4.9.3, (USE: cxx fortran gcj multilib nls nptl openmp sanitize), building libgjsmdssi.so fails unless jack-audio-connection-kit is installed with abi_x86_32 libtool: link: /home/portage/tmp/portage/sys-devel/gcc-4.9.3/work/build/./gcc/xgcc -B/home/portage/tmp/portage/sys-devel/gcc-4.9.3/work/build/./gcc/ -B/usr/x86_64-pc-linux-gnu/bin/ -B/usr/x86_64-pc-linux-gnu/lib/ -isystem /usr/x86_64-pc-linux-gnu/include -isystem /usr/x86_64-pc-linux-gnu/sys-include -m32 -shared .libs/gnu_javax_sound_midi_dssi_DSSIMidiDeviceProvider.o .libs/gnu_javax_sound_midi_dssi_DSSISynthesizer.o ../../../native/jni/classpath/.libs/jcl.o -ljack -m32 -march=native -mtune=native -m32 -m32 -Wl,-soname -Wl,libgjsmdssi.so -o .libs/libgjsmdssi.so /usr/x86_64-pc-linux-gnu/bin/ld: skipping incompatible /usr/lib/libjack.so when searching for -ljack /usr/x86_64-pc-linux-gnu/bin/ld: cannot find -ljack
*** This bug has been marked as a duplicate of bug 444762 ***