Makefile.am:

  do link_sources only once

libmysql_r/Makefile.am

@@ -41,6 +41,7 @@ link_sources:
 	    @LN_CP_F@ $$d/$$f $$f; \
 	  done; \
 	done
+	echo timestamp > link_sources
 
 # Don't update the files from bitkeeper
 %::SCCS/s.%

sql/Makefile.am

@@ -161,6 +161,7 @@ link_sources:
 	@LN_CP_F@ $(top_srcdir)/sql-common/my_time.c my_time.c
 	rm -f my_user.c
 	@LN_CP_F@ $(top_srcdir)/sql-common/my_user.c my_user.c
+	echo timestamp > link_sources
 
 # This generates lex_hash.h
 # NOTE Built sources should depend on their sources not the tool