--- loslib.c	2020-02-14 12:04:26.000000000 +0100
+++ loslib_mobile.c	2020-02-14 12:03:59.000000000 +0100
@@ -140,6 +140,7 @@
 
 static int os_execute (lua_State *L) {
   const char *cmd = luaL_optstring(L, 1, NULL);
+#if !defined(__IPHONE_8_1)  && !defined (__ANDROID__)
   int stat = system(cmd);
   if (cmd != NULL)
     return luaL_execresult(L, stat);
@@ -147,6 +148,10 @@
     lua_pushboolean(L, stat);  /* true if there is a shell */
     return 1;
   }
+#else 
+    lua_pushboolean(L, -1);  /* a problem */
+    return 1;  
+#endif
 }
 
 
