Fix HTML help code to work with 32 & 64 bit builds

Copies THHAKLink record definition from UHTMLHelp unit into UHTMLHelpMgr
unit.

Modified THTMLHelpMgr in UHTMLHelpMgr to be compatible with both 32 and
64 bit calls to the HTML Help API.

Removed UHTMLHelp unit from project. Earlier compilers didn't have a
translation of the HTML Help C headers, so a custom written one was
used. Delphi has had such a translation in the Windows unit for quite
some time now, so this has been used in place of UHTMLHelp. The decision
was made to change because the Windows unit contains 32/64 bit
compatible function prototypes whilst the custom code only supported 32
bit prototypes.

Author: delphidabbler

Src/CodeSnip.Caboli.dpr

@@ -245,7 +245,6 @@ uses
   UHiddenRichEdit in 'UHiddenRichEdit.pas',
   UHistory in 'UHistory.pas',
   UHistoryMenus in 'UHistoryMenus.pas',
-  UHTMLHelp in 'UHTMLHelp.pas',
   UHTMLHelpMgr in 'UHTMLHelpMgr.pas',
   UHTTPProtocol in 'UHTTPProtocol.pas',
   UIniDataLoader in 'UIniDataLoader.pas',

Src/CodeSnip.Caboli.dproj

@@ -490,7 +490,6 @@
         <DCCReference Include="UHiddenRichEdit.pas"/>
         <DCCReference Include="UHistory.pas"/>
         <DCCReference Include="UHistoryMenus.pas"/>
-        <DCCReference Include="UHTMLHelp.pas"/>
         <DCCReference Include="UHTMLHelpMgr.pas"/>
         <DCCReference Include="UHTTPProtocol.pas"/>
         <DCCReference Include="UIniDataLoader.pas"/>

Src/UHTMLHelp.pas

@@ -24,7 +24,7 @@ implementation
   // Delphi
   Windows,
   // Project
-  UAppInfo, UEncodings, UHTMLHelp, UHelpMgr;
+  UAppInfo, UEncodings, UHelpMgr;
 
 
 type
@@ -37,7 +37,7 @@   THTMLHelpMgr = class(TInterfacedObject,
   )
   strict private
     procedure DoAppHelp(const Command: LongWord; const HelpPage: string;
-      const Data: LongWord);
+      const Data: NativeUInt);
       {Calls HtmlHelp API with specified command and parameters.
         @param Command [in] Command to send to HTML Help.
         @param HelpPage [in] Name of HTML file containing required help page
@@ -54,10 +54,27 @@   THTMLHelpMgr = class(TInterfacedObject,
       }
   end;
 
+  {
+  THHAKLink:
+    Structure used to specify one or more ALink names or KLink keywords to be
+    searched for.
+  }
+  THHAKLink = packed record
+    cbStruct: Integer;    // sizeof this structure
+    fReserved: BOOL;      // must be FALSE (really!)
+    pszKeywords: LPCTSTR; // semi-colon separated keywords
+    pszUrl: LPCTSTR;      // URL to jump to if no keywords found (may be nil)
+    pszMsgText: LPCTSTR;  // MessageBox text on failure (used if pszUrl nil)
+    pszMsgTitle: LPCTSTR; // Title of any failure MessageBox
+    pszWindow: LPCTSTR;   // Window to display pszURL in
+    fIndexOnFail: BOOL;   // Displays index if keyword lookup fails.
+  end;
+
+
 { THTMLHelpMgr }
 
 procedure THTMLHelpMgr.DoAppHelp(const Command: LongWord;
-  const HelpPage: string; const Data: LongWord);
+  const HelpPage: string; const Data: NativeUInt);
   {Calls HtmlHelp API with specified command and parameters.
     @param Command [in] Command to send to HTML Help.
     @param HelpPage [in] Name of HTML file containing required help page within
@@ -98,7 +115,7 @@ procedure THTMLHelpMgr.ShowHelp(const AKeyword: string);
   ALink.pszKeywords := Pointer(StringToASCIIString(AKeyword));
   ALink.fIndexOnFail := True;
   // Display help
-  DoAppHelp(HH_ALINK_LOOKUP, '', LongWord(@ALink));
+  DoAppHelp(HH_ALINK_LOOKUP, '', DWORD_PTR(@ALink));
 end;
 
 initialization