Ticket #3029: configure.ac: warning about unknown '--with-' / '--enable-' options.
As we use 'AC_CONFIG_SUBDIRS' macro for samba sources option checking is
disabled for us.
Before the patch:
$ ./configure --with-i-have-misspelled-editor-for-edit
...
# no warnings
The patch enables warnings back only for top-level ./configure:
$ ./configure --with-i-have-misspelled-editor-for-edit
...
configure: WARNING: unrecognized options: --with-i-have-misspelled-editor-for-edit
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>