0022972: Eliminate macro definitions that has compiler-provided analogs (WNT and so on)

1) Macro definition WNT replaced by _WIN32 and _MSC_VER for platform and compiler detection accordingly.
2) Macro definition LIN replaced by __linux__ macro.
3) Macro definition DEB replaced by OCCT_DEBUG macro.

src/DDataStd/DDataStd_BasicCommands.cxx

@@ -1232,7 +1232,7 @@ static Standard_Integer DDataStd_KeepUTF (Draw_Interpretor& di,
     DDF::AddLabel(DF, arg[2], L);
     Standard_CString aFileName(arg[3]);
 
-#ifdef WNT
+#ifdef _MSC_VER
       ifstream anIS (aFileName, ios::in | ios::binary);
 #else
       ifstream anIS (aFileName);
@@ -1304,7 +1304,7 @@ static Standard_Integer DDataStd_GetUTFtoFile (Draw_Interpretor& di,
 
     Standard_CString aFileName(arg[3]);
 
-#ifdef WNT
+#ifdef _MSC_VER
     ofstream anOS (aFileName, ios::in | ios::binary | ios::ate);
 #else
     ofstream anOS (aFileName, ios::ate);

src/DDataStd/DDataStd_DrawDisplayCommands.cxx

@@ -52,7 +52,7 @@
 #include <DDataStd_DrawPresentation.hxx>
 #include <DDataStd_DrawDriver.hxx>
 
-#ifndef WNT
+#ifndef _WIN32
 extern Draw_Viewer dout;
 #else
 Standard_IMPORT Draw_Viewer dout;

src/DDataStd/DDataStd_DrawPresentation.cxx

@@ -31,7 +31,7 @@
 #include <TDF_RelocationTable.hxx>
 #include <TDF_Tool.hxx>
 
-#ifndef WNT
+#ifndef _WIN32
 extern Draw_Viewer dout;
 #else
 Standard_IMPORT Draw_Viewer dout;