Update to v1.8.

Changes from 1.7:
v1.8 2007/04/09
	(2007/04/08) PS1 - portability: use 'test' instead of '[' in shell
	scripts.
	(2007/04/08) PS1 - test suite: run PDF checks as a separate test.
	(2007/04/06) PS1 - fixed logical expressions in flate.c
	(2007/02/19) PS1 - portability: replacements for inline and M_PI
	(2007/01/16) PS1 - test suite: added checks for rotation in
	PostScript, PDF, and PGM backends
	(2007/01/16) PS1 - pdf backend: added rotation
	(2007/01/16) PS1 - pdf backend: renamed shipcom() function
	(2007/01/14) PS1 - autoconf: check if getopt_long reorders its
	arguments.
	(2007/01/13) PS1 - made pseudo-random number generation
	thread-safe and much faster.
	(2006/12/20) PS1 - renamed some structures in lzw.c, main.h
	(2006/12/20) PS1 - portability: fixed some compiler issues for
	Amiga, reported by Andreas Kleinert.
	(2006/12/20) PS1 - main.c: changed some return types to void.
	(2006/08/14) PS1 - made curve.c:privcurve_free_members() static.
	(2005/12/22) PS1 - renamed README.win as README-WIN
	(2005/11/11) PS1 - portability: use binary file i/o in Cygwin.
	Suggested by Henry He.
	(2005/06/24) PS1 - potracelib: fixed allocation bug, reported by
	Jung Shin.
	(2005/06/23) PS1 - potracelib_demo.c: free resources properly.
	(2005/06/23) PS1 - initialize unused private state to 0.
	(2005/06/23) PS1 - decompose.c: improved memory allocation scheme.
	(2005/05/06) PS1 - added "alphacurve" field to private curve
	structure, so that backends that don't use the public interface
	(such as the EPS backend) can be warned of non-conforming curves.


(sborrill)