make cast nicer

io/iob_send.c

@@ -5,10 +5,7 @@
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <stdlib.h>
-#if defined(__linux__)
-#include <alloca.h>
-#endif
-
+#include "havealloca.h"
 #include "iob_internal.h"
 #include "havebsdsf.h"
 
@@ -23,7 +20,7 @@ int64 iob_send(int64 s,io_batch* b) {
 #endif
 
   if (b->bytesleft==0) return 0;
-  last=array_start(&b->b)+array_bytes(&b->b);
+  last=(iob_entry*)(((char*)array_start(&b->b))+array_bytes(&b->b));
   v=alloca(b->bufs*sizeof(struct iovec));
   total=0;
   for (;;) {