autoupdate fun

[Ralf Wildenhues]

A couple of issues with autoupdate (and a call for an m4 wizard :-)

The first bug has been reported against Libtool several moons ago by
Dalibor Topic.  I've now stumbled over it again and nailed it down to
AC_LANG_SAVE.  Namely,
  AC_LANG_SAVE
  AC_LANG_SAVE

will lead to m4 looping endlessly.  Smalles useful configure.ac:
  AC_INIT
  AC_LANG_SAVE
  AC_LANG_RESTORE
  AC_LANG_SAVE
  AC_LANG_RESTORE

This prevents users of Libtool to successfully use autoupdate,
because we use AC_LANG_SAVE twice in libtool.m4.  ATM I don't
even know whether we can get rid of it (support for older
Autoconf releases etc).


The second bug: AS_HELP_STRING arguments are not quoted after
autoupdate.  I assume this is another bug in AU_ALIAS:
  AC_HELP_STRING([--enable-foo], [foo bar])

will turn into
  AS_HELP_STRING(--enable-foo,foo bar)

Cheers,
Ralf