Fix headers_install.pl and headers_check.pl to be compatible with versions
of Perl less than 5.6.0.  It has been tested with Perl 5.005_03 and 5.8.8.
I realize this may not be an issue for most people, but there will still
be some that hit it, I imagine.  There are three basic issues:

1. Prior to 5.6.0 open() only used 2 arguments, and the versions of
the scripts in 2.6.27.1 use 3.
2. 5.6.0 also introduced the ability to use uninitialized scalar
variables as file handles, which the current scripts make use of.
3. Lastly, 5.6.0 also introduced the pragma 'use warnings'. We can use
the -w switch and be backwards compatible.
Signed-off-by: NJeremy Huntwork <jhuntwork@lightcubesolutions.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

We see some header files that are selected dependent on
the actual architecture so force a reinstallation
of all header files when the arch changes.
This slows down "make headers_check_all" but then
we better reflect reality.
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

Move the core functionality of headers_install
and headers_check to two small perl scripts.
The makefile is adapted to use the perl scrip and
changed to operate on all files in a directory.
So if one file is changed then all files in the
directory is processed.

perl were chosen for the helper scripts because this
is pure text processing which perl is good at and
especially the headers_check.pl script are expected to
see changes / new checks implmented.

The speed is ~300% faster on this box.
And the output generated to the screen is now down to
two lines per directory (one for install, one for check)
so it is easier to scroll back after a kernel build.

The perl scripts has been brought to sanity by patient
feedback from: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>