change length or size specifiers in APIs from int to long

add array API (http://cr.yp.to/lib/array.html)

array/array_truncate.c

@@ -0,0 +1,17 @@
+#ifdef __dietlibc__
+#include <sys/cdefs.h>
+#else
+#define __likely(x) x
+#define __unlikely(x) x
+#endif
+#include "safemult.h"
+#include "array.h"
+
+/* I'm not sure I understand what this function is good for */
+void array_truncate(array* x,uint64 membersize,int64 len) {
+  uint64 wanted;
+  if (__unlikely(len<0)) return;
+  if (__unlikely(umult64(membersize,len,&wanted))) return;
+  if (__unlikely(wanted > x->initialized)) return;
+  x->initialized=wanted;
+}