Create a common BR2_COPYTO to prepare to replace

all the different COPYTOs spread out all over
Buildroot.
Generate COPY_FILE subroutine which can be used
to copy a file.

$(COPY_FILE , file, directory, filename)
This will copy to binary dir and to the selected
copy dir if set in new config (intended to replace
all old COPYTO configs)

This is overridden by BUILDROOT_COPYTO,
if set into the environment.

Config.in

@@ -69,6 +69,13 @@ config BR2_DL_DIR
 
 	  The default is $(BASE_DIR)/dl
 
+config BR2_COPYTO
+	string "Copy result to..."
+	default ""
+	help
+	  Setting this variable will (eventually) override 
+	  any other copyto configurations in buildroot.
+
 source	"target/device/Config.in.mirrors"
 
 config BR2_STAGING_DIR