Move "ar" flags to config.mk to allow for silent "make -s" ...

Based on patch by Mike Frysinger, 20 Jun 2006

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.

GCC-4.x fixes: clean up global data pointer initialization for all boards.

Coding Style cleanup

Add missing Blackfin files.