If you want to go the glibc2.1.x route stick with x=3. It is the one giving the least problems and has stable pthread support for the powerpc. The pthread support was somehow flaky both for x=1 and x=2 (in my experience). Just dont forget to apply the necessary patches (Cacheline size patch and fpu patch) and dont to forget to remove the memset.S file!!!!
I also have been playing with diffrent libraries (although now I am just using glibc 2.1.3) and what I did is that installed just couple of "embedded filesystem" which I could switch between just by changing the export file for the NFS server. ( I am booting the boards over NFS). Hope this helps, K.D. ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
