eric@teckel ~ $ /usr/bin/tclsh
% package require tclreadline
couldn't load file "/usr/lib/libtclreadline.so":
/usr/lib/libtclreadline.so: undefined symbol: _rl_executing_macro
This is with readline 6.2_p1 and tclreadline 2.1.0-r1 on Gentoo Linux.
At readline 4.2 we have:
_rl_executing_macro has been renamed to rl_executing_macro, which
means it's now part of the public interface.
so it presumably hasn't worked since then!