Now that we require a recent version of autoconf, we can rely on this
macro working. We shift the call in configure.ac down a little to
help keep the generated diff minimal -- there should be no functional
difference otherwise. This is because the autoconf macros will call
a bunch of standard toolchain macros first, and arguably the current
code is incorrect in how it does its testing.
The AC_LIBTOOL_WIN32_DLL macro has been deprecated for a while and code
should call LT_INIT with win32-dll instead. Update the calls to match.
The generated code is noisy not because of substantial differences, but
because the order of some macros change (i.e. instead of calling AS and
then CC, CC is called first and then AS).
The newlib & libgloss dirs are already generated using autoconf-2.69.
To avoid merging new code and/or accidental regeneration using diff
versions, leverage config/override.m4 to pin to 2.69 exactly. This
matches what gcc/binutils/gdb are already doing.
The README file already says to use autoconf-2.69.
To accomplish this, it's just as simple as adding -I flags to the
top-level config/ dir when running aclocal. This is because the
override.m4 file overrides AC_INIT to first require the specific
autoconf version before calling the real AC_INIT.