linux-arm: unroll loops that may benefit

Summary: This option is *not* the same as -funroll-all-loops. Let's unroll any loop that may benefit according to gcc.

Test Plan: test stability and please report back.

Reviewers: randall.rushing, Mustaavalkosta, michyprima, Roach, synergy

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D232

Change-Id: I684dca506753f81c05fffb330632007eb8243f88

Conflicts:
	core/combo/TARGET_linux-arm.mk
linux-arm: enable link time optimization globally

Summary:
Main commit for the global link time optimization patchset.

Depends on D236
Depends on D237
Depends on D238
Depends on D239
Depends on D240
Depends on D241

Test Plan: apply all patches and win

Reviewers: randall.rushing, Mustaavalkosta, Roach, rlasalle15

Differential Revision: http://review.codefirex.com/D242

Change-Id: I8ac184793a46b6f324d26c0de2c763868b144748

Conflicts:
	core/combo/TARGET_linux-arm.mk