AC_CONFIG_LINKS with source file in the build tree

[Alexandre Duret-Lutz]

AC_CONFIG_FILES and AC_CONFIG_HEADERS both handle inputs files
in the build tree.  (For instance on output of AC_CONFIG_FILES can
be used as input for another AC_CONFIG_FILES.)

The code for _AC_OUTPUT_FILES and AC__OUTPUT_HEADERS have
a section with

  # First look for the input files in the build tree, otherwise in the
  # src tree.

However this is not the case of AC_CONFIG_LINKS.  I've just
discovered this while writing a test case for Automake.
_AC_OUTPUT_SUBDIRS expects the source of a link to be in the
source tree.

  if test ! -r $srcdir/$ac_source; then
    AC_MSG_ERROR([$srcdir/$ac_source: file not found])
  fi

I wonder if this is deliberate or if this is just an oversight.
This looks bogus to me.  For instance I think it would make
sense to output several config files with AC_CONFIG_FILES, and
then make a link to one of them with AC_CONFIG_LINKS.

--
Alexandre Duret-Lutz