Share code to show pre-remove/post-install msgs.

lib/Makefile

@@ -36,6 +36,7 @@ EXTOBJS = external/dewey.o external/fexec.o external/mkpath.o
 OBJS = package_configure.o package_config_files.o package_orphans.o
 OBJS += package_remove.o package_find_obsoletes.o package_state.o
 OBJS += package_unpack.o package_register.o package_script.o verifysig.o
+OBJS += package_msg.o
 OBJS += transaction_commit.o transaction_package_replace.o
 OBJS += transaction_dictionary.o transaction_sortdeps.o transaction_ops.o
 OBJS += transaction_revdeps.o pubkey2fp.o