arm: upgrade to _FORTIFY_SOURCE=2

Enable _FORTIFY_SOURCE=2 for ARM.

Currently, this change is a no-op, as Android's libc doesn't
support _FORTIFY_SOURCE > 1, yet.

Change-Id: Ib4c8e44e6949a37352c153e3c52a4fa001f18738
Duplicate libgcc.a in front of *so

Also see 6c7bc550adb917157a9f53ebf8898110e37294b2

Change-Id: Iade6cd6b40cd4840a148098e1d8fc7a0c97e2f66
Run zipalign after classes.dex is removed from the apk

If LOCAL_DEX_PREOPT is enabled.

Change-Id: Ie2a706fbb77bc31c9fdb01c8435819c5de97ea28
Don't build emulator

thanks to dhacker29