Fixes for Xcode 5 and OSX 10.9.
kernel.mk: Put elf.h into the include path on Darwin builds.

Change-Id: I7069b956965d27caac3b2e4c3cc2e8b4c1da7a82
Merge branch 'cm-10.1' of github.com:CyanogenMod/android_build into cm-10.1