Commit 0b516ef0 added version.o to all
executables, but broke out-of-tree builds: for those builds the pattern
rule %.o: %.rc from rules.mak does not match, so version.o was no longer
built.

Adding explicit build rules fixes this.

Reported-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com>