2012/03/30 - Mark Hatle <mark.hatle@windriver.com>
 - Initial Revision

The ARM architecture definitions are split among a number of files.
The primary definitions for the variables are handled by the core
arch-arm.inc file.

TUNE_ARCH is set to either "arm" or "armeb" depending on the value
of the existence of the "bigendian" feature in a given tune.

A small set of ARM specific variables have been defined to allow
TUNE_PKGARCH to be automatically defined.  Optimized tunings must NOT
change the definiton of TUNE_PKGARCH.  TUNE_PKGACH:tune-<tune> will be
ignored.  The format of the package arch is enforced by the TUNE_PKGARCH
default.  The format must be of the form:
<armversion>[t][e][hf][b][-vfp][-neon]

TUNE_PKGARCH is defined as:
${ARMPKGARCH}${ARMPKGSFX_THUMB}${ARMPKGSFX_DSP}${ARMPKGSFX_EABI}${ARMPKGSFX_ENDIAN}${ARMPKGSFX_FPU}

ARMPKGARCH - This is the core package arch component specified by each
tuning.  This is the primary identifier of a tuning.  Usual values are:
arm, armv4, armv5, armv6, armv7a, etc.

ARMPKGSFX_THUMB - This is the thumb specific suffix.  Curently it is
defined in feature-arm-thumb.inc.

ARMPKGSFX_DSP - This is the DSP specific suffix.  Currently this is set
to 'e' when on armv5 and the dsp feature is enabled.

ARMPKGSFX_EABI - This is the eabi specific suffix.  There are currently
two defined ABIs specificed, standard EABI and Hard Float (VFP) EABI.
When the callconvention-hard is enabled, "hf" is specified, otherwise it
is blank.

ARMPKGSFX_ENDIAN - This is the endian specific suffix.  It is defined in
the core arch-arm.inc file.

ARMPKGSFX_FPU - This is the FPU specific suffix.  The suffix indicates
specific FPU optimizations.  'vfp' and 'neon' are both defined.