[PATCH] kbuild scripts: replace gawk, head, bc with shell, update

  Replacing overhead of using some (external) programs
  instead of good old `sh'.

Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: William Stearns <wstearns@pobox.com>
Cc: Martin Schlemmer <azarah@nosferatu.za.org>
Signed-off-by: Oleg Verych <olecom@flower.upol.cz>
Acked-by: Mark Lord <lkml@rtr.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>