General unqueue_signal problem

["Andrej Borsenkow" <Andrej.Borsenkow@xxxxxxxxxxxxxx>]

> cc -qlanglvl=ansi  -s  -o zftp.so -bI:../../Src/zsh.export
> -bE:zftp.export -emodentry zftp..o  ../../Src/modentry..o  -ldl -lcurses
> -lm  -lc
> ld: 0711-317 ERROR: Undefined symbol: .handler

This comes from unqueue_signals() macro. This macro directly calls handler()
from signals.c (at least, I presume it is this one). But as I understand,
zftp.c sometimes install its own handler. Any other module may possible
install own handler as well.

I do not understand how signal queuing works - anybody cares to check it? It
is trivial to add mod_export to handler deinition - but I do not like it. At
least, we should change the name then. handler is too cute for a globally
visible function.

-andrej