the new glibc-2.1 breaks source compatibility with xterm(patch98) and SSH-2.1.26. Also there is a binary compatibility problem with blackdown4s JDK which can be worked around by using either native_threads(get glibc native package and "export THREADS_FLAG=native") or probably the libc5 version.
I seem to have read somewhere that undefining HAVE_UTMPX_H in the offending source for ssh fixes the problem, but I haven't tested that.
The fix for ssh-1.2.26 is add -D_GNU_SOURCE to CFLAGS, compile and delete the bogus line that the compile fails on. (The line is already deleted in ssh-1.2.27). I'm closing this bug because a) xterm(patch98) is part of XFree86 (I assume). b) ssh is not a Red Hat package and the fixes are available. c) the broken blackdown JDK is already mentioned in several other bug reports and will be solved there not here.