cumentation</A>.
This section describes the low-level mechanisms used to control
the optional parts of the library that are configured at build
time.   Control is based on
a collection of C defines that are specified either on the compiler
command line or in a configuration file such as <TT>port.h</TT>
(as generated by the <TT>configure</TT> script for UNIX systems)
or <B>tiffconf.h</B>.

<P>
Configuration defines are split into three areas:
<UL>
<LI>those that control which compression schemes are
    conf