Merge pull request #1056 from fd00/use-dev-urandom-on-cygwin

Use `/dev/urandom` for `janet_cryptorand` on cygwin

Author: bakpakin

src/core/util.c

@@ -869,7 +869,7 @@ int janet_cryptorand(uint8_t *out, size_t n) {
         }
     }
     return 0;
-#elif defined(JANET_LINUX) || ( defined(JANET_APPLE) && !defined(MAC_OS_X_VERSION_10_7) )
+#elif defined(JANET_LINUX) || defined(JANET_CYGWIN) || ( defined(JANET_APPLE) && !defined(MAC_OS_X_VERSION_10_7) )
     /* We should be able to call getrandom on linux, but it doesn't seem
        to be uniformly supported on linux distros.
        On Mac, arc4random_buf wasn't available on until 10.7.

src/include/janet.h

@@ -67,6 +67,11 @@ extern "C" {
 #define JANET_LINUX 1
 #endif
 
+/* Check for Cygwin */
+#if defined(__CYGWIN__)
+#define JANET_CYGWIN 1
+#endif
+
 /* Check Unix */
 #if defined(_AIX) \
     || defined(__APPLE__) /* Darwin */ \