[cairo] PDF backend requires zlib

[Jason Dorje Short]

Apparently the PDF backend also requires zlib and compress().  This 
patch makes configure check for that too.

Note 1.  The new checks put the module error info into the $use_xxx 
variable, so you get nice output like

   PDF: no (requires zlib http://www.gzip.org/zlib/)

at the end of your configure run.

Some of the old checks use AC_MSG_WARN for this (which gives a similar 
message but it may be lost in all the configure output).  These should 
probably be made consistent - perhaps even using both methods of warning.

-jason
-------------- next part --------------
A non-text attachment was scrubbed...
Name: pdf.diff
Type: text/x-patch
Size: 1468 bytes
Desc: not available
Url : http://lists.freedesktop.org/archives/cairo/attachments/20050330/89bf1092/pdf.bin