'make dist' fails to detect git change on FreeBSD

[Assaf Gordon]

Hello (again),

On FreeBSD 10, "make dist" does not detect git changes.
(This is perhaps not a direct "GNU-Hello" bug, but it's the easiest to 
reproduce with it).

On FreeBSD 10:

    $ git clone git://git.savannah.gnu.org/hello.git
    $ cd hello
 
    # (skip-po because default FreeBSD doesn't have wget+rsync, required for PO)
    $ ./bootstrap --skip-po

    # "out-of-the-box" version, "dirty" because bootstrapping GNULIB changed 
".gitignore"
    $ ./build-aux/git-version-gen .foo
    2.9.31-fa3c-dirty
    $ git status -s
     M .gitignore

    # Build this version, as-is
    $ ./configure
    $ make
    $ make dist
    $ ls hello-*.tar.gz
    hello-2.9.31-fa3c-dirty.tar.gz

    # Change a file, commit new version
    $ echo "hello world" >> README
    $ git status -s
    M .gitignore
    M README
    $ git commit -a -m "dummy ci"
    [master 67fe777] dummy ci
    2 files changed, 4 insertions(+)

    # This is the new version string
    $ ./build-aux/git-version-gen .foo
    2.9.32-67fe

    # running 'make dist' does not detect the git change.
    # On Linux, it would detect it and run "autoreconf".
    $ make dist
    make  dist-gzip am__post_remove_distdir='@:'
    if test -d "hello-2.9.31-fa3c-dirty"; then  find "hello-2.9.31-fa3c-dirty" 
-t
    ...
    ...
    

Programs are:

    $ git --version | head -n1
    git version 1.8.5.4
    $ automake --version | head -n1
    automake (GNU automake) 1.14
    $ autoconf --version | head -n1
    autoconf (GNU Autoconf) 2.69
    $ autoreconf --version | head -n1
    autoreconf (GNU Autoconf) 2.69
    $ uname -a
    FreeBSD clubbsd 10.0-RELEASE FreeBSD 10.0-RELEASE #0 r260789: Thu Jan 16 
22:34:59 UTC 2014     address@hidden:/usr/obj/usr/src/sys/GENERIC  amd64

Regards,
 -gordon