Fix link to the "pexports" tool. Found by Joe Aikkaravelil on docs@.

Doc/install/index.rst

@@ -1046,7 +1046,7 @@ These compilers require some special libraries.  This task is more complex than
 for Borland's C++, because there is no program to convert the library.  First
 you have to create a list of symbols which the Python DLL exports. (You can find
 a good program for this task at
-http://www.emmestech.com/software/pexports-0.43/download_pexports.html).
+http://sourceforge.net/projects/mingw/files/MinGW/Extension/pexports/).
 
 .. I don't understand what the next line means. --amk
 .. (inclusive the references on data structures.)