Disable compatibility decomposition usage during normalization

Fixes https://github.com/behdad/harfbuzz/issues/152

src/hb-ot-shape-normalize.cc

@@ -171,28 +171,6 @@ decompose (const hb_ot_shape_normalize_context_t *c, bool shortest, hb_codepoint
   return 0;
 }
 
-/* Returns 0 if didn't decompose, number of resulting characters otherwise. */
-static inline unsigned int
-decompose_compatibility (const hb_ot_shape_normalize_context_t *c, hb_codepoint_t u)
-{
-  unsigned int len, i;
-  hb_codepoint_t decomposed[HB_UNICODE_MAX_DECOMPOSITION_LEN];
-  hb_codepoint_t glyphs[HB_UNICODE_MAX_DECOMPOSITION_LEN];
-
-  len = c->buffer->unicode->decompose_compatibility (u, decomposed);
-  if (!len)
-    return 0;
-
-  for (i = 0; i < len; i++)
-    if (!c->font->get_glyph (decomposed[i], 0, &glyphs[i]))
-      return 0;
-
-  for (i = 0; i < len; i++)
-    output_char (c->buffer, decomposed[i], glyphs[i]);
-
-  return len;
-}
-
 static inline void
 decompose_current_character (const hb_ot_shape_normalize_context_t *c, bool shortest)
 {
@@ -207,8 +185,6 @@ decompose_current_character (const hb_ot_shape_normalize_context_t *c, bool shor
     skip_char (buffer);
   else if (!shortest && c->font->get_glyph (u, 0, &glyph))
     next_char (buffer, glyph);
-  else if (decompose_compatibility (c, u))
-    skip_char (buffer);
   else
     next_char (buffer, glyph); /* glyph is initialized in earlier branches. */
 }