Fix a serious bug in make(1)'s handling of archive libraries.

This case did not need to be tested when RANLIBMAG was defined
(as when in an `aout' environment) because Arch_StatMember() treated
the two cases of the library not being present and a member of
the library not being present the same way, forcing a rebuild
of the library.  Since in the ELF environment we don't look inside
archive libraries we now need to check if the archive library is
present in order to determine its `out-of-date'-ness.

(I hope I've been able to meet the Oct 15th freeze).

Reported-by:	Steve Price (and a few others whom I've forgotten, sorry)

usr.bin/make/arch.c

@@ -35,7 +35,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id$
+ *	$Id: arch.c,v 1.8 1997/02/22 19:27:05 peter Exp $
  */
 
 #ifndef lint
@@ -1187,7 +1187,7 @@ Arch_LibOODate (gn)
 	    oodate = TRUE;
 	}
 #else
-	oodate = FALSE;
+	oodate = (gm->mtime == 0); /* out-of-date if not present */
 #endif
     }
     return (oodate);