Add configure options --enable-symlink-build and --enable-symlink-install

These options allow e2fsprogs to be built using symlinks instead of
hard links, and to be installed using symlinks instead of hard links,
respectively.

Addresses-Sourceforge-Bug: #1436294

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/lib/Makefile.checker b/lib/Makefile.checker
index cdc1d7b..7bff0f4 100644
--- a/lib/Makefile.checker
+++ b/lib/Makefile.checker
@@ -13,4 +13,5 @@
 	$(Q) (cd checker; $(ARGEN) $@ $(OBJS))
 	-$(Q) $(RANLIB) $@
 	$(Q) $(RM) -f ../$@
-	$(Q) $(LN) $@ ../$@
+	$(Q) (cd .. ; $(LN) $(LINK_BUILD_FLAGS) \
+	     `echo $(my_dir) | sed -e 's;lib/;;'`/$@ $@)