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

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 43021

Makefile

@@ -15,6 +15,7 @@ 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

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

include/target.mk

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