We only support SDK version 21 and up
We only support SDK version 21 and up

* Older SDKs are missing lots of symbols in libc, e.g.:
  * __ctype_get_mb_cur_max
  * atof
  * sigemptyset
  * sigaddset
* See https://github.com/android/platform_bionic/blob/62767bc31dc7c5de1c9f64cce682acef6c5e3a25/libc/include/signal.h#L116

ryantrinkle/try-reflex,reflex-frp/reflex-platform,reflex-frp/reflex-platform,reflex-frp/reflex-platform