Use absolute directory names substituted by configure
* lisp/Makefile.in (top_srcdir): Define.
(abs_top_builddir): Define.
(srcdir): Don't append `/..'.
(EMACS): Use ${abs_top_builddir}.
(all, compile, compile-always, compile-last): Don't set emacswd.
(update-subdirs, update-authors): Use $(top_srcdir) instead of
$(srcdir).
(lisp): Use $(srcdir) instead of @srcdir@.
* src/Makefile.in (abs_builddir): Define.
(bootstrap_exe): Use it.
(VPATH): Use $(srcdir) instead of @srcdir@.