DO NOT MERGE: proper implementation of "askfirst" shell

Now it matches full implementation submitted upstream:
http://patchwork.ozlabs.org/patch/420980/

Signed-off-by: Alexey Brodkin <[email protected]>

Author: abrodkin

system/Config.in

@@ -311,6 +311,11 @@ config BR2_TARGET_GENERIC_GETTY_OPTIONS
 endmenu
 endif
 
+config BR2_TARGET_ASKFIRST_SHELL
+	bool "Start an \"askfirst\" shell on the console (whatever that may be)"
+	depends on BR2_INIT_BUSYBOX
+	depends on !BR2_TARGET_GENERIC_GETTY
+
 config BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW
 	bool "remount root filesystem read-write during boot"
 	default y

system/skeleton/etc/inittab

@@ -24,7 +24,7 @@ null::sysinit:/bin/hostname -F /etc/hostname
 ::sysinit:/etc/init.d/rcS
 
 # Start an "askfirst" shell on the console (whatever that may be)
-::askfirst:-/bin/sh
+#::askfirst:-/bin/sh # ASKFIRST_SHELL
 
 # Put a getty on the serial port
 #ttyS0::respawn:/sbin/getty -L ttyS0 115200 vt100 # GENERIC_SERIAL

system/system.mk

@@ -76,6 +76,15 @@ endif
 TARGET_FINALIZE_HOOKS += SYSTEM_GETTY
 endif
 
+ifeq ($(BR2_TARGET_ASKFIRST_SHELL),y)
+# Add askfirst shell to busybox inittab
+define SYSTEM_ASKFIRST
+	$(SED) '/# ASKFIRST_SHELL$$/s~^.*#~::askfirst:-/bin/sh #~' \
+		$(TARGET_DIR)/etc/inittab
+endef
+TARGET_FINALIZE_HOOKS += SYSTEM_ASKFIRST
+endif
+
 ifeq ($(BR2_TARGET_GENERIC_REMOUNT_ROOTFS_RW),y)
 # Find commented line, if any, and remove leading '#'s
 define SYSTEM_REMOUNT_RW