Introduced auto behavior to the fix-bad-comments option so that yes or

`no` could be applied automatically per the document type. This is the new
default.

localize/translations/tidy.pot

@@ -5,7 +5,7 @@ msgstr ""
 "Plural-Forms: nplurals=2; plural=n != 1;\n"
 "X-Generator: HTML Tidy poconvert.rb\n"
 "Project-Id-Version: \n"
-"POT-Creation-Date: 2017-09-24 18:12:27\n"
+"POT-Creation-Date: 2017-09-25 15:18:12\n"
 "Last-Translator: jderry\n"
 "Language-Team: \n"
 
@@ -466,7 +466,9 @@ msgid ""
 "This option specifies if Tidy should replace unexpected hyphens with "
 "<code>=</code> characters when it comes across adjacent hyphens. "
 "<br/>"
-"The default is <var>no</var>. "
+"The default is <var>auto</var> will which will act as <var>no</var> "
+"for HTML5 document types, and <var>yes</var> for all other document "
+"types. "
 "<br/>"
 "HTML has abandonded SGML comment syntax, and allows adjacent hypens "
 "for all versions of HTML, although XML and XHTML do not. If you plan "

src/config.c

@@ -61,7 +61,7 @@ static PickListItems boolPicks = {
 static PickListItems autoBoolPicks = {
     { "no",   TidyNoState,   { "0", "n", "f", "no",  "false", NULL } },
     { "yes",  TidyYesState,  { "1", "y", "t", "yes", "true",  NULL } },
-    { "auto", TidyYesState, { "auto",                        NULL } },
+    { "auto", TidyAutoState, { "auto",                        NULL } },
     { NULL }
 };
 
@@ -241,7 +241,7 @@ static const TidyOptionImpl option_defs[] =
     { TidyEscapeCdata,             MU, "escape-cdata",                BL, no,              ParsePickList,     &boolPicks          },
     { TidyEscapeScripts,           PP, "escape-scripts",              BL, yes,             ParsePickList,     &boolPicks          }, /* 20160227 - Issue #348 */
     { TidyFixBackslash,            MU, "fix-backslash",               BL, yes,             ParsePickList,     &boolPicks          },
-    { TidyFixComments,             MU, "fix-bad-comments",            BL, no,              ParsePickList,     &boolPicks          },
+    { TidyFixComments,             MU, "fix-bad-comments",            IN, TidyAutoState,   ParsePickList,     &autoBoolPicks      },
     { TidyFixUri,                  MU, "fix-uri",                     BL, yes,             ParsePickList,     &boolPicks          },
     { TidyForceOutput,             MS, "force-output",                BL, no,              ParsePickList,     &boolPicks          },
     { TidyGDocClean,               MU, "gdoc",                        BL, no,              ParsePickList,     &boolPicks          },

src/language_en.h

@@ -476,7 +476,9 @@ static languageDefinition language_en = { whichPluralForm_en, {
         "This option specifies if Tidy should replace unexpected hyphens with "
         "<code>=</code> characters when it comes across adjacent hyphens. "
         "<br/>"
-        "The default is <var>no</var>. "
+        "The default is <var>auto</var> will which will act as <var>no</var> "
+        "for HTML5 document types, and <var>yes</var> for all other document "
+        "types. "
         "<br/>"
         "HTML has abandonded SGML comment syntax, and allows adjacent hypens "
         "for all versions of HTML, although XML and XHTML do not. If you plan "

src/lexer.c

@@ -2613,7 +2613,22 @@ static Node* GetTokenFromStream( TidyDocImpl* doc, GetTokenMode mode )
     Bool isempty = no;
     AttVal *attributes = NULL;
     Node *node;
-    Bool fixComments = cfgBool(doc, TidyFixComments);
+    Bool fixComments;
+    
+    switch ( cfgAutoBool(doc, TidyFixComments) )
+    {
+        case TidyYesState:
+            fixComments = yes;
+            break;
+
+        case TidyNoState:
+            fixComments = no;
+            break;
+
+        default:
+            fixComments = (TY_(HTMLVersion)(doc) & HT50) == 0;
+            break;
+    }
 
     /* Lexer->token must be set on return. Nullify it for safety. */
     lexer->token = NULL;