Merge commits from ruby core repository.

  * https://github.com/ruby/ruby/commit/1852b4a8660ee8e71997f81cee4903c6eb23f306
  * https://github.com/ruby/ruby/commit/c70f12c288cec94d3a7079ee3ffac3ee606d29ff
  * https://github.com/ruby/ruby/commit/4911d45648d03a519a3c93ca04649705a10fe149
  * https://github.com/ruby/ruby/commit/af14720f749ea0274cadd4fa0329b86567ae0057
  * https://github.com/ruby/ruby/commit/e3b4cd38dfe6df2545bf7a3dee01f9b4a78e94d0
  * https://github.com/ruby/ruby/commit/1493972e8234cd5d57881d2353d153aa7cd67e72
  * https://github.com/ruby/ruby/commit/208d2a95f5cceeeec0f619e4700bb6971e41f677
  * https://github.com/ruby/ruby/commit/865decb508e89960382fc41d239be3e42545b68a

5 files changed, 22 insertions, 28 deletions

diff --git a/ext/psych/psych_emitter.c b/ext/psych/psych_emitter.c
index 2154470..55bd417 100644
--- a/ext/psych/psych_emitter.c
+++ b/ext/psych/psych_emitter.c
@@ -192,8 +192,8 @@ static VALUE start_document(VALUE self, VALUE version, VALUE tags, VALUE imp)
 	    name = rb_str_export_to_enc(name, encoding);
 	    value = rb_str_export_to_enc(value, encoding);
 
-	    tail->handle = (yaml_char_t *)RSTRING_PTR(name);
-	    tail->prefix = (yaml_char_t *)RSTRING_PTR(value);
+	    tail->handle = (yaml_char_t *)StringValueCStr(name);
+	    tail->prefix = (yaml_char_t *)StringValueCStr(value);
 
 	    tail++;
 	}
@@ -272,8 +272,8 @@ static VALUE scalar(
 
     yaml_scalar_event_initialize(
 	    &event,
-	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValuePtr(anchor)),
-	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValuePtr(tag)),
+	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
+	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
 	    (yaml_char_t*)StringValuePtr(value),
 	    (int)RSTRING_LEN(value),
 	    plain ? 1 : 0,
@@ -319,8 +319,8 @@ static VALUE start_sequence(
 
     yaml_sequence_start_event_initialize(
 	    &event,
-	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValuePtr(anchor)),
-	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValuePtr(tag)),
+	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
+	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
 	    implicit ? 1 : 0,
 	    (yaml_sequence_style_t)NUM2INT(style)
 	    );
@@ -383,8 +383,8 @@ static VALUE start_mapping(
 
     yaml_mapping_start_event_initialize(
 	    &event,
-	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValuePtr(anchor)),
-	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValuePtr(tag)),
+	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor)),
+	    (yaml_char_t *)(NIL_P(tag) ? NULL : StringValueCStr(tag)),
 	    implicit ? 1 : 0,
 	    (yaml_mapping_style_t)NUM2INT(style)
 	    );
@@ -432,7 +432,7 @@ static VALUE alias(VALUE self, VALUE anchor)
 
     yaml_alias_event_initialize(
 	    &event,
-	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValuePtr(anchor))
+	    (yaml_char_t *)(NIL_P(anchor) ? NULL : StringValueCStr(anchor))
 	    );
 
     emit(emitter, &event);
diff --git a/ext/psych/psych_yaml_tree.c b/ext/psych/psych_yaml_tree.c
index bcf24d2..7aca911 100644
--- a/ext/psych/psych_yaml_tree.c
+++ b/ext/psych/psych_yaml_tree.c
@@ -9,7 +9,7 @@ VALUE cPsychVisitorsYamlTree;
  */
 static VALUE private_iv_get(VALUE self, VALUE target, VALUE prop)
 {
-    return rb_attr_get(target, rb_intern(StringValuePtr(prop)));
+    return rb_attr_get(target, rb_intern(StringValueCStr(prop)));
 }
 
 void Init_psych_yaml_tree(void)
diff --git a/ext/psych/yaml/emitter.c b/ext/psych/yaml/emitter.c
index 5adcbde..580a8d2 100644
--- a/ext/psych/yaml/emitter.c
+++ b/ext/psych/yaml/emitter.c
@@ -24,8 +24,8 @@
  */
 
 #define PUT_BREAK(emitter)                                                      \
-    (FLUSH(emitter)                                                             \
-     && ((emitter->line_break == YAML_CR_BREAK ?                                \
+    (FLUSH(emitter) ?                                                             \
+      ((emitter->line_break == YAML_CR_BREAK ?                                \
              (*(emitter->buffer.pointer++) = (yaml_char_t) '\r') :              \
           emitter->line_break == YAML_LN_BREAK ?                                \
              (*(emitter->buffer.pointer++) = (yaml_char_t) '\n') :              \
@@ -34,7 +34,7 @@
               *(emitter->buffer.pointer++) = (yaml_char_t) '\n') : 0),          \
          emitter->column = 0,                                                   \
          emitter->line ++,                                                      \
-         1))
+         1) : 0)
 
 /*
  * Copy a character from a string into buffer.
@@ -221,7 +221,7 @@ yaml_emitter_write_indent(yaml_emitter_t *emitter);
 
 static int
 yaml_emitter_write_indicator(yaml_emitter_t *emitter,
-        char *indicator, int need_whitespace,
+        const char *indicator, int need_whitespace,
         int is_whitespace, int is_indention);
 
 static int
@@ -1784,7 +1784,7 @@ yaml_emitter_write_indent(yaml_emitter_t *emitter)
 
 static int
 yaml_emitter_write_indicator(yaml_emitter_t *emitter,
-        char *indicator, int need_whitespace,
+        const char *indicator, int need_whitespace,
         int is_whitespace, int is_indention)
 {
     size_t indicator_length;
@@ -2178,7 +2178,7 @@ yaml_emitter_write_block_scalar_hints(yaml_emitter_t *emitter,
         yaml_string_t string)
 {
     char indent_hint[2];
-    char *chomp_hint = NULL;
+    const char *chomp_hint = NULL;
 
     if (IS_SPACE(string) || IS_BREAK(string))
     {
diff --git a/ext/psych/yaml/parser.c b/ext/psych/yaml/parser.c
index dc5430b..32671b2 100644
--- a/ext/psych/yaml/parser.c
+++ b/ext/psych/yaml/parser.c
@@ -759,9 +759,8 @@ yaml_parser_parse_block_sequence_entry(yaml_parser_t *parser,
 
     else if (token->type == YAML_BLOCK_END_TOKEN)
     {
-        yaml_mark_t dummy_mark;     /* Used to eliminate a compiler warning. */
         parser->state = POP(parser, parser->states);
-        dummy_mark = POP(parser, parser->marks);
+        (void)POP(parser, parser->marks);
         SEQUENCE_END_EVENT_INIT(*event, token->start_mark, token->end_mark);
         SKIP_TOKEN(parser);
         return 1;
@@ -869,9 +868,8 @@ yaml_parser_parse_block_mapping_key(yaml_parser_t *parser,
 
     else if (token->type == YAML_BLOCK_END_TOKEN)
     {
-        yaml_mark_t dummy_mark;     /* Used to eliminate a compiler warning. */
         parser->state = POP(parser, parser->states);
-        dummy_mark = POP(parser, parser->marks);
+        (void)POP(parser, parser->marks);
         MAPPING_END_EVENT_INIT(*event, token->start_mark, token->end_mark);
         SKIP_TOKEN(parser);
         return 1;
@@ -952,7 +950,6 @@ yaml_parser_parse_flow_sequence_entry(yaml_parser_t *parser,
         yaml_event_t *event, int first)
 {
     yaml_token_t *token;
-    yaml_mark_t dummy_mark;     /* Used to eliminate a compiler warning. */
 
     if (first) {
         token = PEEK_TOKEN(parser);
@@ -997,7 +994,7 @@ yaml_parser_parse_flow_sequence_entry(yaml_parser_t *parser,
     }
 
     parser->state = POP(parser, parser->states);
-    dummy_mark = POP(parser, parser->marks);
+    (void)POP(parser, parser->marks);
     SEQUENCE_END_EVENT_INIT(*event, token->start_mark, token->end_mark);
     SKIP_TOKEN(parser);
     return 1;
@@ -1104,7 +1101,6 @@ yaml_parser_parse_flow_mapping_key(yaml_parser_t *parser,
         yaml_event_t *event, int first)
 {
     yaml_token_t *token;
-    yaml_mark_t dummy_mark;     /* Used to eliminate a compiler warning. */
 
     if (first) {
         token = PEEK_TOKEN(parser);
@@ -1158,7 +1154,7 @@ yaml_parser_parse_flow_mapping_key(yaml_parser_t *parser,
     }
 
     parser->state = POP(parser, parser->states);
-    dummy_mark = POP(parser, parser->marks);
+    (void)POP(parser, parser->marks);
     MAPPING_END_EVENT_INIT(*event, token->start_mark, token->end_mark);
     SKIP_TOKEN(parser);
     return 1;
diff --git a/ext/psych/yaml/scanner.c b/ext/psych/yaml/scanner.c
index 3ef90dc..d8d9032 100644
--- a/ext/psych/yaml/scanner.c
+++ b/ext/psych/yaml/scanner.c
@@ -1186,11 +1186,9 @@ yaml_parser_increase_flow_level(yaml_parser_t *parser)
 static int
 yaml_parser_decrease_flow_level(yaml_parser_t *parser)
 {
-    yaml_simple_key_t dummy_key;    /* Used to eliminate a compiler warning. */
-
     if (parser->flow_level) {
         parser->flow_level --;
-        dummy_key = POP(parser, parser->simple_keys);
+	(void)POP(parser, parser->simple_keys);
     }
 
     return 1;
@@ -1638,7 +1636,7 @@ yaml_parser_fetch_key(yaml_parser_t *parser)
 
     if (!parser->flow_level)
     {
-        /* Check if we are allowed to start a new key (not nessesary simple). */
+        /* Check if we are allowed to start a new key (not necessary simple). */
 
         if (!parser->simple_key_allowed) {
             return yaml_parser_set_scanner_error(parser, NULL, parser->mark,