Changes made to pristine png source by mozilla.org developers.

2002/02/15  -- Synced with 1.0.9 tree
Reapplied following changes:

Bug 78649 - Wrapped stderr fprintfs inside DEBUG ifdef.
	Affected files: pnggccrd.c, ipng.cpp, if.cpp

Bug 81794 - crash/leak fix for pngrutil.c
	Affected files: pngrutil.c