Fix Imakefile so that it works better with the X11R4 installation.
This includes commenting out BINDIR, CDEBUGFLAGS, and MANPATH.
Thanks to David Eckelkamp@MCC and Carl Witty@Stanford for their
recommentations, and specially David Eckelkamp@MCC for his improvements.
NOTE: With the current setup, those who wishes to install tgif
in places outside of the X11R4 installation has to modify
the Imakefile (uncomment the definition for CDEBUGFLAGS,
BINDIR, MANPATH, and redefine TGIFDIR). Sorry for the