+# It makes debugging easier if we create as symlinks the stage directories
+# gcc for stageN-gcc and stage-prev for stage(N-1). In case this is not
+# possible, however, we can resort to mv.
+AC_CACHE_CHECK([if symbolic links between directories work],
+[gcc_cv_prog_ln_s_dir],
+[if test "${LN_S}" = "ln -s" \
+ && mkdir confdir.s1 \
+ && ln -s confdir.s1 confdir.s2 \
+ && echo timestamp1 > confdir.s1/conftest.1 \
+ && cmp confdir.s1/conftest.1 confdir.s2/conftest.1 \
+ && echo timestamp2 > confdir.s2/conftest.2 \
+ && cmp confdir.s1/conftest.2 confdir.s1/conftest.2 \
+ && rm -f confdir.s2; then
+ gcc_cv_prog_ln_s_dir=yes
+else
+ gcc_cv_prog_ln_s_dir=yes
+fi
+rm -rf confdir.s1 confdir.s2])
+
+case ${gcc_cv_prog_ln_s_dir} in
+ yes)
+ CREATE_LINK_TO_DIR='ln -s $$1 $$2'
+ UNDO_LINK_TO_DIR='rm -f $$1' ;;
+ *)
+ CREATE_LINK_TO_DIR='mv $$1 $$2'
+ UNDO_LINK_TO_DIR='mv $$1 $$2' ;;
+esac
+AC_SUBST(CREATE_LINK_TO_DIR)
+AC_SUBST(UNDO_LINK_TO_DIR)
+