THESE PROGRAMS ARE DEFINITELY 32 BIT
SystemC is perfectly happy on x86_64 however the pre-compiled libraries shipped inside the Designware System Library are not. Ah-ha, you say, "I shall compile them in 32 bit mode". However there is a problem: they depend on qt-devel.i386 which can't be installed on the same system as qt-devel.x86_64. So there.
Another word of warning for the clever:
THE BUILD SCRIPTS WILL WORK, BUT GENERATE EXECUTABLES THAT SEGFAULT.
Make/g++ don't quit on the qt linking error. Several hours of condensed hacking wasted as I didn't spot it. Another reason to use virtual machines to avoid these kinds of problems when using CAD tools. [see above for more details on the segfault issues]