The media-gfx/blender-2.42a ebuild DEPENDs on =dev-util/scons-0.96.1 (do to problems with =dev-util/scons-0.96.90, bug #99243), however, the current scons (=dev-util/scons-0.96.92-r3) can build blender. DEPEND="=dev-util/scons-0.96.1 || ( x11-libs/libXt virtual/x11 ) ${RDEPEND}"
The ebuilds in portage nolong depend on a specific version of scons.