mrdb, mirb: Add fflush() so that a external program can read output immediately.

mrbgems/mruby-bin-debugger/tools/mrdb/mrdb.c

@@ -480,6 +480,7 @@ get_and_parse_command(mrb_state *mrb, mrdb_state *mrdb)
   while (!cmd) {
     for (p=NULL; !p || *p=='\0'; ) {
       printf("(%s:%d) ", mrdb->dbg->prvfile, mrdb->dbg->prvline);
+      fflush(stdout);
       p = get_command(mrb, mrdb);
     }
 

mrbgems/mruby-bin-mirb/tools/mirb/mirb.c

@@ -281,6 +281,7 @@ print_cmdline(int code_block_open)
   else {
     printf("> ");
   }
+  fflush(stdout);
 }
 #endif