Follow-up r325342: Always ensure WORLDTMP exists.

Reported by:	Herbert J. Skuhra
Sponsored by:	Dell EMC Isilon

Makefile.inc1

@@ -815,7 +815,6 @@ _worldtmp: .PHONY
 	@echo "--------------------------------------------------------------"
 .if !defined(NO_CLEAN)
 	rm -rf ${WORLDTMP}
-	@mkdir -p ${WORLDTMP}
 .else
 .if exists(${WORLDTMP})
 	@echo ">>> Deleting stale files in build tree..."
@@ -832,6 +831,7 @@ _worldtmp: .PHONY
 .endfor
 .endif	# ${USING_SYSTEM_COMPILER} == "yes"
 .endif	# !defined(NO_CLEAN)
+	@mkdir -p ${WORLDTMP}
 	@touch ${WORLDTMP}/${.TARGET}
 
 .for _dir in \