META MODE: Don't truncate DIRDEPS for bootstrapping during gendirdeps.

Reviewed by:	sjg
Sponsored by:	EMC / Isilon Storage Division

share/mk/meta.autodep.mk

@@ -191,7 +191,7 @@ gendirdeps:	${_DEPENDFILE}
 # anything which matches ${_OBJROOT}* but not ${_OBJTOP}*
 # needs to be qualified in DIRDEPS
 # The pseudo machine "host" is used for HOST_TARGET
-DIRDEPS = \
+DIRDEPS += \
 	${DPADD:M${_OBJTOP}*:H:C,${_OBJTOP}[^/]*/,,:N.:O:u} \
 	${DPADD:M${_OBJROOT}*:N${_OBJTOP}*:H:S,${_OBJROOT},,:C,^([^/]+)/(.*),\2.\1,:S,${HOST_TARGET}$,host,:N.*:O:u}