Merge pull request #338 from pitdicker/osrng_extra_check

 Try /dev/random before using /dev/urandom

Author: dhardy

CHANGELOG.md

@@ -70,7 +70,9 @@ You may also find the [Update Guide](UPDATING.md) useful.
 - Add support for CloudABI. (#224)
 - Remove support for NaCl. (#225)
 - WASM support for `OsRng` via stdweb, behind the `stdweb` feature. (#272, #336)
+- Use `getrandom` on more platforms for Linux, and on Android. (#338)
 - On systems that do not have a syscall interface, only keep a single file descriptor open for `OsRng`. (#239)
+- On Unix, first try a single read from `/dev/random`, then `/dev/urandom`. (#338)
 - Better error handling and reporting in `OsRng` (using new error type). (#225)
 - `OsRng` now uses non-blocking when available. (#225)
 - Add `EntropyRng`, which provides `OsRng`, but has `JitterRng` as a fallback. (#235)