use C style comments instead of C++ style comments

mrbgems/mruby-string-utf8/src/string.c

@@ -608,7 +608,7 @@ mrb_str_split_m(mrb_state *mrb, mrb_value str)
 
       while (ptr < eptr &&
         (end = mrb_memsearch(sptr, slen, ptr, eptr - ptr)) >= 0) {
-        //        mrb_ary_push(mrb, result, str_subseq(mrb, str, ptr - temp, end));
+        /*        mrb_ary_push(mrb, result, str_subseq(mrb, str, ptr - temp, end)); */
         mrb_ary_push(mrb, result, mrb_str_new(mrb, ptr, end));
         mrb_gc_arena_restore(mrb, ai);
         ptr += end + slen;

src/proc.c

@@ -153,11 +153,11 @@ mrb_proc_arity(mrb_state *mrb, mrb_value self)
   int ma, ra, pa, arity;
 
   if (MRB_PROC_CFUNC_P(p)) {
-    // TODO cfunc aspec not implemented yet
+    /* TODO cfunc aspec not implemented yet */
     return mrb_fixnum_value(-1);
   }
 
-  // arity is depend on OP_ENTER
+  /* arity is depend on OP_ENTER */
   if (GET_OPCODE(*iseq) != OP_ENTER) {
     return mrb_fixnum_value(0);
   }

src/string.c

@@ -1799,7 +1799,7 @@ mrb_str_split_m(mrb_state *mrb, mrb_value str)
     }
   }
   else if (split_type == string) {
-    char *ptr = RSTRING_PTR(str); // s->as.ary
+    char *ptr = RSTRING_PTR(str); /* s->as.ary */
     char *temp = ptr;
     char *eptr = RSTRING_END(str);
     mrb_int slen = RSTRING_LEN(spat);