I am building ATLAS 3.7.20 on a 4-CPU Xeon machine and ATLAS tries to make a 64bit build but the toolchain is all 32bit hence compilation fails.
So I wonder if there is a configure flag to force ATLAS to do 32bit build?
I give the configure script the "-m 32" flag, hope that helps.
Sorry, I meant "-b 32". This is the configure command I use with GCC 3.4.4 and Cygwin:
../ATLAS/configure -v 2 -b 32 -D c -DPentiumCPS=3900