Trailing whitespace in input causes GCL to forget to
print the next input prompt.
(%i1) a : 100; <-- there is a space character after
the semicolon here
(%i3) a : 200$ <-- there is a space character after
the dollar sign here
Same behavior for Maxima 5.9.3cvs / GCL 2.6.7 / Linux,
and Maxima 5.9.3 / GCL 2.6.7 / Win XP.
Behavior not observed with SBCL or Clisp.
Could be readline strangeness, although Clisp has
readline and it is OK (i.e., input prompts are printed