On Android bzero() is a macro.

diff -u -r ../openssh-7.4p1/openbsd-compat/explicit_bzero.c ./openbsd-compat/explicit_bzero.c
--- ../openssh-7.4p1/openbsd-compat/explicit_bzero.c	2016-12-18 23:59:41.000000000 -0500
+++ ./openbsd-compat/explicit_bzero.c	2016-12-20 19:57:24.595833810 -0500
@@ -25,12 +25,12 @@
 
 #else /* HAVE_MEMSET_S */
 
-/*
- * Indirect bzero through a volatile pointer to hopefully avoid
- * dead-store optimisation eliminating the call.
- */
-static void (* volatile ssh_bzero)(void *, size_t) = bzero;
-
+/*
+ * Indirect memset through a volatile pointer to hopefully avoid
+ * dead-store optimisation eliminating the call.
+ */
+static void* (* volatile ssh_memset)(void *, int, size_t) = memset;
+
 void
 explicit_bzero(void *p, size_t n)
 {
@@ -45,7 +45,7 @@
 # endif
 #endif
 
-	ssh_bzero(p, n);
+	ssh_memset(p, 0, n);
 }
 
 #endif /* HAVE_MEMSET_S */