[Interest] more problems with virtual frame buffer

[Duane]

I've built a desktop version of 4.8.1 open source and I'm trying to make 
the qvfb binary.  I get a series of errors involving png_*  like 
png_structp does not name a type.

I have png support built.  I have libpng installed.  I've seen a few 
posts on the web with this same issue but no solution.  I'm using Fedora 
16.  My colleague using the latest Ubuntu doesn't have this issue.  What 
am I missing?