- * TODO: enrich the list of detected system. Also add detection for
- * alternate system calls like getentropy(), which are usually
- * preferable when available.
+ * Win32's CryptGenRandom() should be available on Windows systems.
+ *
+ * /dev/urandom should work on all Unix-like systems (including macOS X).
+ *
+ * getentropy() is present on Linux (Glibc 2.25+), FreeBSD (12.0+) and
+ * OpenBSD (5.6+). For OpenBSD, there does not seem to be easy to use
+ * macros to test the minimum version, so we just assume that it is
+ * recent enough (last version without getentropy() has gone out of
+ * support in May 2015).
+ *
+ * Ideally we should use getentropy() on macOS (10.12+) too, but I don't
+ * know how to test the exact OS version with preprocessor macros.
+ *
+ * TODO: enrich the list of detected system.