With openmpi-1.6.4 the configure for octave, shogun and mathgl hangs while detection of C-compiler, see Bug 462990, Bug 463220 and Bug 462672. If openmpi-1.6.4 is masked and openmpi-1.6.3 is reemerged the hanging disappears. Reproducible: Always
*** This bug has been marked as a duplicate of bug 462990 ***