Found a typo in the 2.4 guide on step 22 for the 32-bit version:
32-bit 22. ./configure.py --cl-inc-dir=/opt/AMD-APP-SDK-v2.4-lnx6432/include/ --cl-lib-dir=/opt/AMD-APP-SDK-v2.4-lnx32/lib/x86
the highlighted 64 should be removed.
I was having the same problem as Schizo during the make -j3 step:
src/wrapper/wrap_cl.hpp:20:19: fatal error: CL/cl.h: No such file or directory
compilation terminated.
error: command 'gcc' failed with exit status 1
make: *** [all] Error 1
After fixing the typo, this error went away, and now everything seems to be working great!