This reverts commit 3da018dde122ae90ff82e9733c096e3c75331fe1.
I can't accept this NDK headers modification due since it introduces
issues for certain programs for unknown reason.
Instead provide langinfo.h with inline implemention of nl_langinfo()
as a system header.
This avoids linking in libandroid-support.so in some places, and
improves compatibility when building code on-device.
