Fix compile-time tests for LP64.

Change-Id: Ib9bec5c6c77c55679d64c2bc15ab70979c40e66c
Merge "Fix compile-time tests for LP64."
Use ln(1) rather than cp(1) to set up host /system for testing.

The trouble with cp is that if you're running a command directly (because
you're using gdb, say), you need to make sure you've copied the linker
and shell again if you've done a rebuild that caused a change there.

Change-Id: I312da30c0f92b515967e854e0faba272c961ecc7
Don't silently return EINVAL for a NULL sem_t*.

Bug: 17571197
Change-Id: Ied31d8de87fc10d20dc338be0457e9a4ddb9a0a5
Merge "Use ln(1) rather than cp(1) to set up host /system for testing."
Merge "Don't silently return EINVAL for a NULL sem_t*."