[oe] autoconf-2.65-r9.0 failing to correctly detect M4 (core)

[GNUtoo]

hi,
I've the following issue:
armv6-angstrom-linux-gnueabi/autoconf-2.65-r9.0/autoconf-2.65$ grep m4
config.log 
configure:2401: result: /usr/bin/m4
which results in the following error at compilation:
| autom4te: need GNU m4 1.4 or later: /usr/bin/m4
| make[2]: *** [autoconf.in] Error 1
| make[2]: Leaving directory
`.../armv6-angstrom-linux-gnueabi/autoconf-2.65-r9.0/autoconf-2.65/bin'
| make[1]: *** [all-recursive] Error 1
| make[1]: Leaving directory
`.../work/armv6-angstrom-linux-gnueabi/autoconf-2.65-r9.0/autoconf-2.65'
| make: *** [all] Error 2
| FATAL: oe_runmake failed

./run.do_configure.2044
results in:
checking for GNU M4 that supports accurate traces...
(cached) /usr/bin/m4


but removing that line: 
export ac_cv_path_M4="${ac_cv_path_M4=/usr/bin/m4}"
in:
do_configure() {
  if true
  then
    export ac_cv_path_PERL="${ac_cv_path_PERL=/usr/bin/perl}"
    export ac_cv_path_M4="${ac_cv_path_M4=/usr/bin/m4}"
    export ac_cv_prog_gnu_m4="${ac_cv_prog_gnu_m4=yes}
  fi
  autotools_do_configure

}

make it configure well:

checking for GNU M4 that supports accurate
traces... /home/gnutoo/embedded/oe/oetmps/bug/sysroots/x86_64-linux/usr/bin/m4

and:
$ grep m4 config.log 
configure:2401:
result: /home/gnutoo/embedded/oe/oetmps/bug/sysroots/x86_64-linux/usr/bin/m4

The issue is that that code in autoconf.inc

do_configure_prepend () {
  if ${@['true', 'false'][bb.data.inherits_class('native', d)]}
  then
    export ac_cv_path_PERL="${ac_cv_path_PERL=${bindir}/perl}"
    export ac_cv_path_M4="${ac_cv_path_M4=${bindir}/m4}"
    export ac_cv_prog_gnu_m4="${ac_cv_prog_gnu_m4=yes}"
  fi
}

autoconf.inc is definitely core and very important...

I was bitbaking illume-image with bug as machine

I don't know why it pulls a non native/cross autoconf...

but anyway some people may want to compile stuff on the target.

use case:
*they don't know how to cross-compile or don't want too(-dev packages
are faster to install) or have issues with cross-compilation
*they have an arm smartbook like the touchbook and want to program on
it.

Denis.