[ptx] Compiling vigra on Windows with MinGW

[Yili Zhao]

Hi,
  I tried to compile vigra on Windows with MinGW, and I want to
vigra with zlib, png, tiff, jpeg and fftw support. I have compiled
fftw-2.1.3 on Windows successfully, then I compiled vigra using the 
libraries and headfiles supplied by pt, but vigra said that the libpng
version was old. I turned to use the libraries and headfiles supplied
by wxWindows, but found that wxWindows compiled zlib to libzlib.a, not
libz.a library. I renamed it, but vigra compiling also failed. I want to
know where can I find the latest sourcecode of zlib, png, tiff and jpeg
library?
  Thanks.

Yili