bionic: linker: fix prelink support

load_bias_ needs to be calculated from the min_vaddr, not the
prelink address

Fixes

couldn't map "libraryname.so" segment 1: Invalid argument

Change-Id: Ibf1fd1d5a0f2c81ce515f5d47412a043ba768247
libc: krait: Re-factor high-performance memcpy for thumb2

The majority of libc under bionic is built for thumb2.  Refactor the
high performance memcpy used in previous builds for thumb2, including
information that can be used for stack-unwinding.

Change-Id: Ib5f7ab354f39313758402ec02b0aea27b15d45fa

Conflicts:
	libc/arch-arm/krait/bionic/memcpy_base.S
(cherry picked from commit cdeb493351044c3116fc0d42a64f33f8215a5886)
(cherry picked from commit 0c524faa937b40178915c9478599b754b6f8f78d)
bionic: call stdio cleanup on exit

As of 61e699a133a4807fe878a6cb0d7190d7c96e21f8, stdio clean up
functions are no longer registered in atexit and must be called
manually via __cleanup.

The issue this fixes is some static binaries linked against bionic
cannot output properly when piped or redirected because the buffer
is not flushed before closing.

This is done by pulling in exit.c (and other dependencies) from
netbsd.

Change-Id: I193e54a6d08900f291550029fe75ce76394d9e22