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/TopOpeBRep/TopOpeBRep.cxx

@@ -18,7 +18,7 @@
 
 #include <TopOpeBRep.hxx>
 
-//#ifdef WNT
+//#ifdef _WIN32
 //#define strcasecmp strcmp Already defined
 //#endif
 //=======================================================================

src/TopOpeBRep/TopOpeBRep_FacesIntersector.cxx

@@ -1190,7 +1190,7 @@ static void MergeWLinesIfAllSegmentsAlongRestriction(IntPatch_SequenceOfLine&
   if (!anWLine.IsNull()) {
     theSlin.Clear();
     theSlin.Append(anWLine);
-#ifdef DEB
+#ifdef OCCT_DEBUG
     cout << "*** TopOpeBRep_FaceIntersector: Merge WLines on Restriction " 
          << ((WLineRank == 1) ? "S1" : "S2") << " to WLine***" << endl;
 #endif