--- a/cbits-unix/init.c
+++ b/cbits-unix/init.c
@@ -1,8 +1,17 @@
 #include <stdint.h>
 #include <unistd.h>
+#if defined(__ANDROID__) && __ANDROID_API__ < 28
+#include <stdlib.h>
+#endif
 
-uint64_t splitmix_init() {
+uint64_t splitmix_init(void) {
 	uint64_t result;
+	/* Bionic exposes getentropy from API 28; arc4random_buf exists earlier. */
+#if defined(__ANDROID__) && __ANDROID_API__ < 28
+	arc4random_buf(&result, sizeof(uint64_t));
+	int r = 0;
+#else
 	int r = getentropy(&result, sizeof(uint64_t));
+#endif
 	return r == 0 ? result : 0xfeed1000;
 }