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/BuS/EB+MCF-EV123/textbase.mk b/board/BuS/EB+MCF-EV123/textbase.mk
index 10106f4..ecde6ed 100644
--- a/board/BuS/EB+MCF-EV123/textbase.mk
+++ b/board/BuS/EB+MCF-EV123/textbase.mk
@@ -1 +1 @@
-TEXT_BASE = 0xF0000000
+TEXT_BASE = 0xFFE00000