Remove macros putc*/getc* from API<21 stdio.h to use

Macros putc, getc and their unlock cousins use internal functions and
variables not necessarily available in future libc.so (*1).  Remove macros
and use functions aleady exists in libc.so instead.

(*1) https://android-review.googlesource.com/#/c/110662/

Change-Id: I3faa2d74de40ef8376119b38f2a39d46ece47d07
2 files changed