Add missing symbols to android-19 libc

Symbols missing from NDK libc but present in the
platform version of libc:

__system_property_add
__system_property_area_init
__system_property_foreach
__system_property_serial
__system_property_set_filename
__system_property_update
__system_property_wait_any
abs
clearerr_unlocked
feof_unlocked
ferror_unlocked
fileno_unlocked
fstatvfs
imaxabs
imaxdiv
labs
llabs
statvfs
swapoff
swapon
timerfd_create
timerfd_gettime
timerfd_settime

Bug: http://b/28864994
Change-Id: I8f5d7716b19d2aa3aeac80db13f2728307a26599
6 files changed