Support building for any other android architecture

This allows e.g. building for mips, as a plain C++ build with
no assembly.
   use global trace in encoder
keep the unrelated changed line
Merge pull request #454 from mstorsjo/android-any-arch

Support building for any other android architecture
Merge pull request #465 from ruil2/encoder_trace

   use global trace in encoder
reviewed at https://rbcommons.com/s/OpenH264/r/176/