Updating top-level autoconf to 2.59

[Joseph S. Myers]

With this patch, configuring with --build=i686-pc-linux-gnu 
--host=i686-pc-linux-gnu --target=i686-pc-linux-gnu all specified 
explicitly results in i686-pc-linux-gnu-gcc and 
i686-pc-linux-gnu-i686-pc-linux-gnu-gcc being installed but no plain 
"gcc".  Installing i686-pc-linux-gnu-i686-pc-linux-gnu-gcc is clearly 
wrong and existing practice is that "gcc" is installed whenever the host 
and target are the same, regardless of the build system and regardless of 
what was or was not specified explicitly.

-- 
Joseph S. Myers
joseph@codesourcery.com