pyqwt fails to install due to https://bugs.gentoo.org/show_bug.cgi?id=558122 . If pyqwt is masked, 'emerge gqrx' fails with: root@lynx:/home_lynx/rose/ISOs(54)# emerge -uvDN --backtrack=30 --exclude "opencv pyqwt" gqrx These are the packages that would be merged, in order: Calculating dependencies... done! !!! All ebuilds that could satisfy ">=dev-python/pyqwt-5.2:5[python_targets_python2_7(-)?,-python_single_target_jython2_5(-),-python_single_target_jython2_7(-),-python_single_target_pypy(-),-python_single_target_pypy3(-),-python_single_target_python3_3(-),-python_single_target_python3_4(-),python_single_target_python2_7(+)]" have been masked. !!! One of the following masked packages is required to complete your request: - dev-python/pyqwt-5.2.0-r1::gentoo (masked by: exclude option) (dependency required by "net-wireless/gnuradio-3.7.8::gentoo" [ebuild]) (dependency required by "net-wireless/gr-osmosdr-0.1.4_p20150730::gentoo" [ebuild]) (dependency required by "net-wireless/gqrx-2.3.2::gentoo" [ebuild]) (dependency required by "gqrx" [argument]) For more information, see the MASKED PACKAGES section in the emerge man page or refer to the Gentoo Handbook.
This is not a bug; it's the correct result of trying to emerge gnuradio when USE=qt4 and pyqwt is masked by the user. Because when you tell portage that it must not use a certain package, and there is a dependency on that package, of course the only thing that portage can do is print an error and stop... As a workaround, simply disable qt4 USE flag for net-wireless/gnuradio in your package.use (unless you really need qt4 gui in gnuradio for whatever reason).