USE_TERMCAP:
If defined, CQP uses termcap/curses functionality to highlight text in
interactive terminal display (including bold font, underlined text, and
colours with experimental -C option).

USE_READLINE:
If defined, CQP uses the included editline library to allow command-line
editing and a command history (which can automatically be saved to a 
disk file in order to be persistent across sessions).  A backport to
the more widespread GNU Readline library (which had to be abandoned for
copyright reasons before CQP became open source) is planned and should
be fairly easy.

EMULATE_SETENV:
SUN Solaris 8 doesn't support the setenv() function to manipulate 
environment variables, so it has to be emulated by a small wrapper
around putenv() (which is available in Solaris, fortunately).
