Fixed counting of newlines in XML declarations

ext/ragel/base_lexer.rl

@@ -306,19 +306,34 @@
     # Machine that processes the contents of an XML declaration tag.
     xml_decl := |*
         xml_decl_end => {
+            if ( lines > 0 )
+            {
+                advance_line(lines);
+
+                lines = 0;
+            }
+
             callback_simple(id_on_xml_decl_end);
+
             fnext main;
         };
 
         # Attributes and their values (e.g. version="1.0").
         identifier => {
+            if ( lines > 0 )
+            {
+                advance_line(lines);
+
+                lines = 0;
+            }
+
             callback(id_on_attribute, data, encoding, ts, te);
         };
 
         squote => start_string_squote;
         dquote => start_string_dquote;
 
-        any;
+        any $count_newlines;
     *|;
 
     # Elements

spec/oga/xml/lexer/xml_declaration_spec.rb

@@ -23,5 +23,32 @@ describe Oga::XML::Lexer do
         [:T_XML_DECL_END, nil, 1]
       ]
     end
+
+    it 'lexes a declaration with a newline after the open tag' do
+      lex("<?xml\n?>").should == [
+        [:T_XML_DECL_START, nil, 1],
+        [:T_XML_DECL_END, nil, 2]
+      ]
+    end
+
+    it 'lexes a declaration with a newline followed by an attribute' do
+      lex("<?xml\na='b'?>").should == [
+        [:T_XML_DECL_START, nil, 1],
+        [:T_ATTR, 'a', 2],
+        [:T_STRING_SQUOTE, nil, 2],
+        [:T_STRING_BODY, 'b', 2],
+        [:T_STRING_SQUOTE, nil, 2],
+        [:T_XML_DECL_END, nil, 2]
+      ]
+    end
+
+    describe 'using an IO as input' do
+      it 'lexes a declaration with a newline after the open tag' do
+        lex_stringio("<?xml\n?>").should == [
+          [:T_XML_DECL_START, nil, 1],
+          [:T_XML_DECL_END, nil, 2]
+        ]
+      end
+    end
   end
 end