Note that if you configure with --enable-maintainer-mode, you will need
special versions of automake, autoconf, libtool and gettext. You will
-find the sources for these in ftp://sourceware.cygnus.com/pub/binutils.
+find the sources for these in the respective upstream directories:
+
+ https://ftp.gnu.org/gnu/autoconf
+ https://ftp.gnu.org/gnu/automake
+ https://ftp.gnu.org/gnu/libtool
+ https://ftp.gnu.org/gnu/gettext
+
+The required versions of the tools for this tree are:
+
+ autoconf 2.69
+ automake 1.15.1
+ libtool 2.2.6
+ gettext 0.16.1
+
+Note - "make distclean" does not work with maintainer mode enabled.
+The Makefiles in the some of the po/ subdirectories depend upon the
+Makefiles in their parent directories, and distclean will delete the
+Makefiles in the parent directories before running the Makefiles in
+the child directories. There is no easy way around this (short of
+changing the automake macros) as these dependencies need to exist in
+order to correctly build the NLS files.
+
+When running the testsuites a minimum version of dejagnu is also needed.
+Dejagnu can be found here:
+
+ https://ftp.gnu.org/gnu/dejagnu/
+
+The minimum version required is:
+
+ dejagnu 1.5.3