[oe] "make clean" on Weston

[Adam Lee]

Neither "bitbake -c clean weston" nor "bitbake -c cleanall weston" seems to
clean the build directory for me.
Is this how it is for autotool project? "make clean" doesn't work either
("no rule to make target clean").

I need my directory cleaned so I can commit only the necessary changes.

/build/workspace/sources/weston$ git status
On branch devtool
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

        modified:   Makefile.am
        modified:   Makefile.in
        modified:   aclocal.m4
        modified:   build-aux/compile
        modified:   build-aux/config.guess
        modified:   build-aux/config.sub
        modified:   build-aux/depcomp
        modified:   build-aux/install-sh
        modified:   build-aux/ltmain.sh
        modified:   build-aux/missing
        modified:   build-aux/test-driver
        modified:   clients/ivi-shell-user-interface.c
        modified:   clients/simple-egl.c
        modified:   clients/simple-touch.c
        modified:   config.h.in
        modified:   configure
        modified:   ivi-shell/hmi-controller.c
        modified:   ivi-shell/ivi-layout.c
        modified:   ivi-shell/ivi-shell.c
        modified:   libweston/input.c
        modified:   libweston/libinput-device.c
        modified:   m4/libtool.m4
        modified:   m4/ltoptions.m4
        modified:   m4/ltsugar.m4
        modified:   m4/ltversion.m4
        modified:   m4/lt~obsolete.m4

Adam