Add support for a saving build objects in a separate directory.
Modifications are based on the linux kernel approach and
support two use cases:

  1) Add O= to the make command line
  'make O=/tmp/build all'

  2) Set environement variable BUILD_DIR to point to the desired location
  'export BUILD_DIR=/tmp/build'
  'make'

The second approach can also be used with a MAKEALL script
'export BUILD_DIR=/tmp/build'
'./MAKEALL'

Command line 'O=' setting overrides BUILD_DIR environent variable.

When none of the above methods is used the local build is performed and
the object files are placed in the source directory.
diff --git a/board/integratorcp/split_by_variant.sh b/board/integratorcp/split_by_variant.sh
index 3a35433..37ae517 100755
--- a/board/integratorcp/split_by_variant.sh
+++ b/board/integratorcp/split_by_variant.sh
@@ -98,14 +98,17 @@
 	echo -n "#undef CONFIG_CM_TCRAM  " 		>> tmp.fil
 	echo    " /* CM may not have TCRAM */" 		>> tmp.fil
 fi
-mv tmp.fil ./include/config.h
+
+mkdir -p ${obj}include
+mkdir -p ${obj}board/integratorcp
+mv tmp.fil ${obj}include/config.h
 # ---------------------------------------------------------
 #  Ensure correct core object loaded first in U-Boot image
 # ---------------------------------------------------------
-sed -r 's/CPU_FILE/cpu\/'$cpu'\/start.o/; s/#.*//' board/integratorcp/u-boot.lds.template > board/integratorcp/u-boot.lds
+sed -r 's/CPU_FILE/cpu\/'$cpu'\/start.o/; s/#.*//' ${src}board/integratorcp/u-boot.lds.template > ${obj}board/integratorcp/u-boot.lds
 # ---------------------------------------------------------
 # Complete the configuration
 # ---------------------------------------------------------
-./mkconfig -a integratorcp arm $cpu integratorcp;
+$MKCONFIG -a integratorcp arm $cpu integratorcp;
 echo "Variant:: $variant with core $cpu"