Re-add external/harfbuzz/ubsan.patch

...after 5aab2900 "tdf#109142: Update to
HarfBuzz 1.4.8".  The parts that were still relevant for 'make check' are:

* 6694ce6b "external/harfbuzz: Work around ASan
  out of bounds warning"

* 99f7aacd "external/harfbuzz:
  -fsanitize=function"

* ca9a08bb "external/harfbuzz: Silence
  -fsanitize=nonnull-attribute" (plus 83a9c8e0
  "build fix")

Change-Id: Ibff2a7c52c5de60ae00744acd2ef481bbb08706c

external/harfbuzz/UnpackedTarball_harfbuzz.mk

@@ -15,6 +15,7 @@ $(eval $(call gb_UnpackedTarball_set_patchlevel,harfbuzz,0))
 
 $(eval $(call gb_UnpackedTarball_add_patches,harfbuzz, \
     external/harfbuzz/clang-cl.patch \
+    external/harfbuzz/ubsan.patch \
 ))
 
 ifneq ($(ENABLE_RUNTIME_OPTIMIZATIONS),TRUE)

external/harfbuzz/ubsan.patch

+--- src/hb-ot-font.cc
++++ src/hb-ot-font.cc
+@@ -138,7 +138,7 @@
+ 	return this->default_advance;
+     }
+ 
+-    return this->table->longMetric[MIN (glyph, (uint32_t) this->num_advances - 1)].advance
++    return static_cast<OT::LongMetric const *>(this->table->longMetric)[MIN (glyph, (uint32_t) this->num_advances - 1)].advance
+ 	 + this->var->get_advance_var (glyph, font->coords, font->num_coords); // TODO Optimize?!
+   }
+ };
+@@ -458,8 +458,9 @@
+ }
+ 
+ static void
+-_hb_ot_font_destroy (hb_ot_font_t *ot_font)
++_hb_ot_font_destroy (void *ot_font_)
+ {
++  hb_ot_font_t *ot_font = static_cast<hb_ot_font_t *>(ot_font_);
+   ot_font->cmap.fini ();
+   ot_font->h_metrics.fini ();
+   ot_font->v_metrics.fini ();
+--- src/hb-private.hh
++++ src/hb-private.hh
+@@ -461,6 +461,7 @@
+   template <typename T>
+   inline const Type *bsearch (T *key) const
+   {
++    if (len == 0) return NULL;
+     return (const Type *) ::bsearch (key, array, len, sizeof (Type), (hb_compare_func_t) Type::cmp);
+   }
+