Linux x64 binary for 1.0.55 uses GLIBC 2.14
... and many popular distributions still use GLIBC 2.13.
This makes the binary useful for a rather small fraction of the Linux x64 population (I'm using Linux Mint 12 fully upgraded, which is based on Ubuntu - since these two are rather popular and use recent software, I assume many other people don't have 2.14 yet).
I had no trouble compiling from sources on GLIBC 2.13, so it looks to me that there is no technical requirement to use GLIBC 2.14 - is there one? I'm worried that people that don't find it fun to compile from sources might jump to the conclusion that 'SBCL is hard to use/install etc.'.
This particular instance of the issue will probably go away by itself given a few weeks/months, but maybe it would be good to avoid using a bleeding edge system to compile binaries.
NOTE: my belief that I'm using 2.13 is based on the output of 'ldd --version'.