The nds32 & spu dirs are using compile tests to look for some
preprocessor defines, but we don't need to compile the code,
just preprocess it. So switch to AC_PREPROC_IFELSE.
The sh dir is using a preprocessor test via grep, but let's
switch it to AC_PREPROC_IFELSE too to be consistent.
This should allow us to drop the uncommon AC_NO_EXECUTABLES call.
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.
Mike Frysinger