Avoid to call memset(). Use the new function kh_fill_flags() instead. This is for compatibility.

include/mruby/khash.h

@@ -75,6 +75,14 @@ static const uint8_t __m[8] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
   void kh_del_##name(kh_##name##_t *h, khint_t x);                      \
   kh_##name##_t *kh_copy_##name(mrb_state *mrb, kh_##name##_t *h);
 
+static inline void
+kh_fill_flags(uint8_t *p, uint8_t c, size_t len)
+{
+  while (len-- > 0) {
+    *p++ = c;
+  }
+}
+
 /* define kh_xxx_funcs
 
    name: hash name
@@ -92,8 +100,8 @@ static const uint8_t __m[8] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
     h->upper_bound = UPPER_BOUND(sz);                                   \
     h->e_flags = (uint8_t *)mrb_malloc(h->mrb, sizeof(uint8_t)*sz/4);   \
     h->d_flags = h->e_flags + sz/8;                                     \
-    memset(h->e_flags, 0xff, sz/8*sizeof(uint8_t));                     \
-    memset(h->d_flags, 0x00, sz/8*sizeof(uint8_t));                     \
+    kh_fill_flags(h->e_flags, 0xff, sz/8);                              \
+    kh_fill_flags(h->d_flags, 0x00, sz/8);                              \
     h->keys = (khkey_t *)mrb_malloc(h->mrb, sizeof(khkey_t)*sz);        \
     h->vals = (khval_t *)mrb_malloc(h->mrb, sizeof(khval_t)*sz);        \
     h->mask = sz-1;                                                     \
@@ -124,8 +132,8 @@ static const uint8_t __m[8] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
   void kh_clear_##name(kh_##name##_t *h)                                \
   {                                                                     \
     if (h && h->e_flags) {                                              \
-      memset(h->e_flags, 0xff, h->n_buckets/8*sizeof(uint8_t));         \
-      memset(h->d_flags, 0x00, h->n_buckets/8*sizeof(uint8_t));         \
+      kh_fill_flags(h->e_flags, 0xff, h->n_buckets/8);                  \
+      kh_fill_flags(h->d_flags, 0x00, h->n_buckets/8);                  \
       h->size = h->n_occupied = 0;                                      \
     }                                                                   \
   }                                                                     \