Stop unwinding when seeing a repeated ip on x86.

Change-Id: I4141bd57eb8240d8ad5db4b77496f096666439ae
Add speed-ups to libunwind.

Add caching of /proc/self/maps data structures.

Add caching of elf image maps attached to the maps data structure.

Add a set of new map api functions to handle creation/destruction of the
maps by external code.

Remove the creation of the maps data structure in the local address space
init.

Change-Id: I0adae397d433fc3902f83a6f377f6889161937e5
Refactor the makefile for aarch64 support.

This is the first step to libunwind aarch64 support. This only allows
compilation of libunwind under asm64 and is missing a lot of functionality.

Change-Id: I3185d4cc0b95594f3930d3d55f1e2b6bf8df2c68
libunwind: build multiple arches

Change-Id: I76f75a16924e09ccddf9dc6fb022c2a70afa121a
bionic no longer has <sys/procfs.h>.

This was in libthread_db/include, but was pretty incomplete and seems
unused by libunwind.

Change-Id: I38dfade90fac074c0c3a123b9543044e66fd232a
Fix memory leak.

Change-Id: Iaf279d86fe1a9384bbc7cfa40e7b1783bb59a223
Merge "Fix memory leak."