make install fails with $bindir = $execdir

Hi *,

  since commit 4ecbc17 (Makefile: install 'git' in execdir,
2009-07-09), included in v1.6.4-rc0, the install fails when $bindir is
equal to $execdir with:

bindir=$(cd '/home/pcl305/sbejar/usr/stow/git/bin' && pwd) && \
        execdir=$(cd '/home/pcl305/sbejar/usr/stow/git/bin' && pwd) && \
        { rm -f "$execdir/git" && \
                test -z "" && \
                ln "$bindir/git" "$execdir/git" 2>/dev/null || \
                cp "$bindir/git" "$execdir/git"; } && \
        { for p in  ..list..of..builtins; do \
                rm -f "$execdir/$p" && \
                ln "$execdir/git" "$execdir/$p" 2>/dev/null || \
                ln -s "git" "$execdir/$p" 2>/dev/null || \
                cp "$execdir/git" "$execdir/$p" || exit; \
          done; } && \
        ./check_bindir "z$bindir" "z$execdir" "$bindir/git-add"
cp: cannot stat `/home/pcl305/sbejar/usr/stow/git/bin/git': No such
file or directory
make: *** [install] Error 1

I understant what happens, but all this is very delicate, so I'll try to fix it but I don't know when. Maybe we need also tests for this.

Santi