adds sudo to "make install" command

for consistency with instructions that show up while installing

Author: Pepe Bawagan

README.md

@@ -97,7 +97,7 @@ find its data directory. You must either:
     ./autogen.sh
     ./configure
     make
-    make install
+    sudo make install
     sudo ldconfig
 
 to move the data files to the standard place, or: