wait4() was incorrectly declared in <sys/wait.h>, but only added to the
C library in Android 4.3 (API level 18) [1]
This patch:
- Removes the wait4() declarations for any <sys/wait.h> header before
API level 19.
- Brings the API level 19 <sys/wait.h> which correctly declares wait4().
- Update the libc.so.functions.txt for API level 19 of all platforms
to include the exported symbol.
NOTE: This does not bring the static libc.a to API level 19, which means
it is stuck at API level 9 for ARM.
See [2] for the corresponding NDK tests.
http://b.android.com/19854
[1] 17a8b0db63
[2] https://android-review.googlesource.com/#/c/72000/
Change-Id: I7735473d177c44f43b09bb6738e9914945cd4d0a
db275132c5