==============================================
IMPORTANT: Tested only with zlib ver. 1.1.3, 
           libpng ver. 1.0.{5,6,8,9,10,12}, 
           jpeg ver. 6b
==============================================

1) You need libpng, zlib and jpeg sources (available, e.g., from
   ftp.uu.net/graphics/[png,jpeg].

2) Their sources must be unpacked in sub-directories of this dir.
   zlib and libpng sources must be in sub-dirs named 'zlib' and
   'libpng' (these fixed names are required by the libpng documentation).
   Example:
   > unzip -d zlib zlib113.zip
   > tar xzvf libpng-1.0.12.tar.gz
   > mv libpng-1.0.12 libpng
   > tar xzvf jpegsrc.v6b.tar.gz
   If jpeg version is different from 6b, edit 'Makefile' and change 
   the definition of JPEGDIR.

3) Then,
   > make
   should build  Rbitmap.dll and install it in R_HOME/bin.
