diff --git a/src/hb-common.cc b/src/hb-common.cc
index 21d3b4117..1484bbb2e 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -219,7 +219,7 @@ struct hb_language_item_t {
   }
 
   inline hb_language_item_t & operator = (const char *s) {
-    lang = (hb_language_t) strdup (s);
+    lang = (hb_language_t) _strdup (s);
     for (unsigned char *p = (unsigned char *) lang; *p; p++)
       *p = canon_map[*p];
 
@@ -518,7 +518,7 @@ hb_user_data_array_t::set (hb_user_data_key_t *key,
     }
   }
   hb_user_data_item_t item = {key, data, destroy};
-  bool ret = !!items.replace_or_insert (item, lock, replace);
+  bool ret = !!items.replace_or_insert (item, lock, replace != 0);
 
   return ret;
 }
diff --git a/src/hb-fallback-shape.cc b/src/hb-fallback-shape.cc
index 9d061a9e8..0cd623e99 100644
--- a/src/hb-fallback-shape.cc
+++ b/src/hb-fallback-shape.cc
@@ -106,7 +106,7 @@ _hb_fallback_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,
    */
 
   hb_codepoint_t space;
-  bool has_space = font->get_glyph (' ', 0, &space);
+  bool has_space = font->get_glyph (' ', 0, &space) != 0;
 
   buffer->clear_positions ();
 
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 05ea0603c..160d7bba2 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -719,7 +719,7 @@ hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
 					   hb_bool_t             zero_context)
 {
   if (unlikely (lookup_index >= hb_ot_layout_from_face (face)->gsub_lookup_count)) return false;
-  OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, zero_context);
+  OT::hb_would_apply_context_t c (face, glyphs, glyphs_length, zero_context != 0);
 
   const OT::SubstLookup& l = hb_ot_layout_from_face (face)->gsub->get_lookup (lookup_index);
 
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 4985eb22b..28acbda4c 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -89,7 +89,7 @@ hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
 
   for (unsigned int table_index = 0; table_index < 2; table_index++) {
     hb_tag_t table_tag = table_tags[table_index];
-    found_script[table_index] = hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
+    found_script[table_index] = hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]) != 0;
     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
   }
 }
diff --git a/src/hb-ot-shape-complex-hangul.cc b/src/hb-ot-shape-complex-hangul.cc
index 6ac18b08b..37c160031 100644
--- a/src/hb-ot-shape-complex-hangul.cc
+++ b/src/hb-ot-shape-complex-hangul.cc
@@ -305,7 +305,7 @@ preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
     {
       /* Have <LV>, <LVT>, or <LV,T> */
       hb_codepoint_t s = u;
-      bool has_glyph = font->has_glyph (s);
+      bool has_glyph = font->has_glyph (s) != 0;
       unsigned int lindex = (s - SBase) / NCount;
       unsigned int nindex = (s - SBase) % NCount;
       unsigned int vindex = nindex / TCount;
diff --git a/src/hb-ot-shape-complex-hebrew.cc b/src/hb-ot-shape-complex-hebrew.cc
index c7b7a5eba..0330c9c1d 100644
--- a/src/hb-ot-shape-complex-hebrew.cc
+++ b/src/hb-ot-shape-complex-hebrew.cc
@@ -68,7 +68,7 @@ compose_hebrew (const hb_ot_shape_normalize_context_t *c,
     0xFB4Au /* TAV */
   };
 
-  bool found = c->unicode->compose (a, b, ab);
+  bool found = c->unicode->compose (a, b, ab) != 0;
 
   if (!found && !c->plan->has_mark)
   {
diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index 772360041..1a1eba095 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -1847,7 +1847,7 @@ decompose_indic (const hb_ot_shape_normalize_context_t *c,
     }
   }
 
-  return c->unicode->decompose (ab, a, b);
+  return c->unicode->decompose (ab, a, b) != 0;
 }
 
 static bool
@@ -1863,7 +1863,7 @@ compose_indic (const hb_ot_shape_normalize_context_t *c,
   /* Composition-exclusion exceptions that we want to recompose. */
   if (a == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
 
-  return c->unicode->compose (a, b, ab);
+  return c->unicode->compose (a, b, ab) != 0;
 }
 
 
diff --git a/src/hb-ot-shape-normalize.cc b/src/hb-ot-shape-normalize.cc
index 8cc64af01..f67ddb100 100644
--- a/src/hb-ot-shape-normalize.cc
+++ b/src/hb-ot-shape-normalize.cc
@@ -88,7 +88,7 @@ decompose_unicode (const hb_ot_shape_normalize_context_t *c,
 		   hb_codepoint_t *a,
 		   hb_codepoint_t *b)
 {
-  return c->unicode->decompose (ab, a, b);
+  return c->unicode->decompose (ab, a, b) != 0;
 }
 
 static bool
@@ -97,7 +97,7 @@ compose_unicode (const hb_ot_shape_normalize_context_t *c,
 		 hb_codepoint_t  b,
 		 hb_codepoint_t *ab)
 {
-  return c->unicode->compose (a, b, ab);
+  return c->unicode->compose (a, b, ab) != 0;
 }
 
 static inline void
@@ -139,7 +139,7 @@ decompose (const hb_ot_shape_normalize_context_t *c, bool shortest, hb_codepoint
       (b && !font->get_glyph (b, 0, &b_glyph)))
     return 0;
 
-  bool has_a = font->get_glyph (a, 0, &a_glyph);
+  bool has_a = font->get_glyph (a, 0, &a_glyph) != 0;
   if (shortest && has_a) {
     /* Output a and b */
     output_char (buffer, a, a_glyph);
diff --git a/src/hb-ot-shape.cc b/src/hb-ot-shape.cc
index a531d7706..e133115fa 100644
--- a/src/hb-ot-shape.cc
+++ b/src/hb-ot-shape.cc
@@ -538,7 +538,7 @@ hb_ot_position_complex (hb_ot_shape_context_t *c)
 {
   bool ret = false;
   unsigned int count = c->buffer->len;
-  bool has_positioning = hb_ot_layout_has_positioning (c->face);
+  bool has_positioning = hb_ot_layout_has_positioning (c->face) != 0;
   /* If the font has no GPOS, AND, no fallback positioning will
    * happen, AND, direction is forward, then when zeroing mark
    * widths, we shift the mark with it, such that the mark