Circular dependencies in lib-src1

[Eli Zaretskii]

The change that added these targets to lib-src/Makefile.in:

    /* These targets copy the scripts into the build directory
    so that they can be run from there in an uninstalled Emacs.  */
    rcs2log: $(srcdir)/rcs2log
            cp -p $(srcdir)/rcs2log rcs2log

    rcs-checkin: $(srcdir)/rcs-checkin
            cp -p $(srcdir)/rcs-checkin rcs-checkin

    grep-changelog: $(srcdir)/grep-changelog
            cp -p $(srcdir)/grep-changelog grep-changelog

    vcdiff: $(srcdir)/vcdiff
            cp -p $(srcdir)/vcdiff vcdiff

causes Make to print a message about circular dependencies when
${srcdir} is "." (i.e., when Emacs is biult in the source tree).
Isn't there a better way to do what they are supposed to do?