Add missing LOCAL_ADDITIONAL_DEPENDENCIES dependency to BUILD_PREBUILT.

Summary: Change-Id: Id7c0e77110653e618d783026cd4b4aeadb3c45ec

Test Plan: win

Reviewers: randall.rushing, synergy

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D351
core: add LOCAL_NO_LTO_SUPPORT to clear_vars

Summary: This was a big mistake

Test Plan: win

Reviewers: randall.rushing

Differential Revision: http://review.codefirex.com/D356
linux-arm-cfx: add global cflag for qcom variants

Summary: Allows us to implement code which may only pertain to legacy or caf variants

Test Plan: win

Reviewers: randall.rushing

Differential Revision: http://review.codefirex.com/D357