Don't define the meaningless SOFTFLOAT for x86.

Change-Id: I9f932ad5d9f731a0de18efb881d02cedf9fcbede
Clean up the x86 and x86_64 _exit_with_stack_teardown implementations.

Change-Id: I4bcbbc53893612bd94643ef07722becb00f91792
Merge "Don't define the meaningless SOFTFLOAT for x86."
Merge "Clean up the x86 and x86_64 _exit_with_stack_teardown implementations."
libc: fix __cxa_atexit implicit declaration

Change-Id: Iacad18b332a717e4485c83df4bd42a850ff7699f
Merge "libc: fix __cxa_atexit implicit declaration"
Merge https://android.googlesource.com/platform/bionic into jb-devel-mr2-release