Add C linkage for __open_2 and __openat_2.

Otherwise Clang mangle them with C++ names.

Change-Id: I844e28d834df8b0752b32d2aadd2013fc8804a43

Conflicts:
	libc/bionic/open.cpp
Don't abort in stdio.getdelim_invalid and stdio.getline_invalid.

Change-Id: Ie1aefed732f4bea77887bddd1be9a0578e247aa3
Add __popcountsi2 to the function compat list.

This is needed if we use Clang to compile Bionic, which won't include
__popcountsi2 anymore as Clang generates inline instructions. However
prebuilt binary blobs still depend on libc.so to resolve __popcountsi2.

Change-Id: I9001a3884c4be250c0ceebcd79922783fae1a0b7
Don't force O_LARGEFILE on LP64.

aarch64's strace is confused by this, and it isn't necessary anyway.

Change-Id: Ib07b649eb1c38ff0296003874f73af78c47bc276

Conflicts:
	libc/bionic/open.cpp