build: change custom -> omni in a few more places

* these weren't changed when the transtition occured - fix them now

Change-Id: I47bedb96ad63a41959baa98e1a265cb616d17918
Allow disabling PIE for dynamically linked executables

arm: Allow disabling PIE for dynamically linked executables

PIE can and does break some binaries that were built without it,
resulting in relocation-related issues (addressing memory
wrongly assumed to be at a fixed position).

Use this as a last resort measure for compatibility with pre-JB
binary blobs, and only if confirmed to fix a broken executable.
If you're not sure, do NOT enable this on a device.

Change-Id: I3b7001e682a6f7a845e62278fe2afa9ccf5552a4

arm: Drop linker script when building without PIE

The current section headers generated by bionic are incompatible
with this (interp is in, ctors were dropped, and other tiny changes
related to Elf32_Dyn). But... we don't actually need this to
disable PIE, so drop it entirely instead of writing a new one.

Change-Id: I3b350a9f6251e60bf52114343d190f3d6d83b216
Merge branch 'android-4.3' of https://github.com/omnirom/android_build into omni43