Update URL for zlib sources and add note about building it as a shared library.

diff --git a/doc/build.html b/doc/build.html
index eb9b9e96e4b20d89c8517393447422a52a076130..d1d759e9439ea1e1a5a9ea9ebd1bfb9d5172fc4e 100644 (file)
--- a/doc/build.html
+++ b/doc/build.html
@@ -17,8 +17,10 @@ http://www.boutell.com/gd/http/gd-2.0.28.tar.gz</a>
 <br>Graphviz also contains a copy of GD 2.0.4, but we will
 remove it eventually so the external library is preferred.
 <li>ZLIB (raster image compression)
-<a href="http://prdownloads.sourceforge.net/libpng/zlib-1.1.4.tar.gz">
-http://prdownloads.sourceforge.net/libpng/zlib-1.1.4.tar.gz</a>
+<a href="http://www.zlib.net/zlib-1.2.3.tar.gz">
+http://www.zlib.net/zlib-1.2.3.tar.gz</a>
+<br>
+NB: Use "./configure -s" to build shared libraries. (See notes in zlib-1.2.3/Makefile)
 <li>FREETYPE (renders text in raster graphics formats)
 <a href="http://prdownloads.sourceforge.net/freetype/freetype-2.1.3.tar.gz">
 http://prdownloads.sourceforge.net/freetype/freetype-2.1.3.tar.gz</a>