Revert "build: use ONESHELL to speed up scanning and the toplevel makefile"

This seems to cause issues on some build hosts, and it is not that
important.

SVN-Revision: 43025

Makefile

@@ -15,7 +15,6 @@ empty:=
 space:= $(empty) $(empty)
 $(if $(findstring $(space),$(TOPDIR)),$(error ERROR: The path to the OpenWrt directory must not include any spaces))
 
-.ONESHELL:
 world:
 
 include $(TOPDIR)/include/host.mk

include/scan.mk

@@ -78,4 +78,3 @@ $(TMP_DIR)/.$(SCAN_TARGET): $(TARGET_STAMP) $(SCAN_STAMP)
 FORCE:
 .PHONY: FORCE
 .NOTPARALLEL:
-.ONESHELL:

include/target.mk

@@ -19,7 +19,6 @@ DEFAULT_PACKAGES.bootloader:=
 
 ifneq ($(DUMP),)
   all: dumpinfo
-  .ONESHELL:
 endif
 
 target_conf=$(subst .,_,$(subst -,_,$(subst /,_,$(1))))