Various things:
* work around -Wnullability-completeness.
* use C++ casts in C++ and C casts in C.
* stop using attributes clang doesn't support (such as `warning`).
* remove duplicate definitions of XATTR_CREATE and XATTR_REPLACE.
Change-Id: I07649e46275b28a23ca477deea119fe843999533
Also clean up some near-miss copyright headers in libm, and remove
some cruft in <grp.h>/<pwd.h> that the script can't automatically
ignore since we stripped all the tabs in those files.
Change-Id: I10796c54dda1ceba87822ae0de26b5d71b54972b
Future API levels aren't known (e.g. 25 could be a maintenance release
of N that doesn't contain any bionic updates), so use a placeholder
macro that we can find and replace with the actual API level before each
release.
Bug: http://b/28178111
Change-Id: I667fe53ea1ac49b64135170fc30d5dbe9df94e29
Not efficient to iterate through given the large number of Android
ids (AID). Compile warning will result if you use these functions,
telling you as much. Not for general consumption, however for
example, some filesystem tests would like to see these to perform
all corners.
About 1/4 second for getpwent, and 1/8 second for getgrent to iterate
through all reserved Android aids.
Bug: 27999086
Change-Id: I7784273b7875c38e4954ae21d314f35e4bf8c2fc
