I just tried a fresh Cactus built today and it failed in my desktop machine with the following error:
/home/bruno/tmp/einstein_dev_maxwell/Cactus/arrangements/Carpet/Carpet/src/SetupGH.cc(363): error: identifier "CPU_COUNT" is undefined int const num_cores = CPU_COUNT(&mask);
This function was introduced in Carpet hg revision 3492 and it seems that it is causing trouble for me due to glib library version installed in my system, version 2.5.81. For versions greater than 2.6, it should be fine according to http://www.kernel.org/doc/man-pages/online/pages/man3/CPU_SET.3.html.
I was wondering if a mechanism could be introduced in order to test the existence or not of CPU_COUNT (according to glib version?) and do not use it in case it is not defined.