igured as part of the builtin codecs,
<LI>those that control support for groups of tags that
    are considered optional, and
<LI>those that control operating system or machine-specific support.
</UL>

<P>
If the define <TT>COMPRESSION_SUPPORT</TT> is <STRONG>not defined</STRONG>
then a default set of compression schemes is automatically
configured:
<UL>
<LI>CCITT Group 3 and 4 algorithms (compression codes 2, 3, 4, and 32771),
<LI>the Macintosh PackBits algorithm (compression 32773),
<LI>a 4-bit run-length