Kill <machine/exec.h>.

Bug: 18546535
Change-Id: I479e003deab21e31eb5caa5393067ed1dc558387
Merge "Kill <machine/exec.h>."
Remove __ARM_HAVE_LDREXD.

No one uses this.

Bug: 18556103
Change-Id: Icecc3a7b5cb0a36960f27d030d8f4f8ee471f86c
Merge "Remove __ARM_HAVE_LDREXD."
Remove __ARM_HAVE_HALFWORD_MULTIPLY.

Bug: 18556103
Change-Id: I17e498539f77ddf7d1fb980ee93155d3c3ccd85e
Merge "Remove __ARM_HAVE_HALFWORD_MULTIPLY."