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/ViewerTest/ViewerTest.cxx

@@ -76,7 +76,7 @@
 #include <Draw_PluginMacro.hxx>
 
 // avoid warnings on 'extern "C"' functions returning C++ classes
-#ifdef WNT
+#ifdef _MSC_VER
 #define _CRT_SECURE_NO_DEPRECATE
 #pragma warning(4:4190)
 #pragma warning (disable:4996)

src/ViewerTest/ViewerTest_ViewerCommands.cxx

@@ -70,7 +70,7 @@
 #include <Prs3d_LineAspect.hxx>
 #include <Prs3d_Root.hxx>
 
-#ifdef WNT
+#ifdef _WIN32
 #undef DrawText
 #endif
 
@@ -196,7 +196,7 @@ Standard_Boolean DragFirst = Standard_False;
 
 //==============================================================================
 
-#ifdef WNT
+#ifdef _WIN32
 static LRESULT WINAPI ViewerWindowProc(
                                        HWND hwnd,
                                        UINT uMsg,
@@ -1864,7 +1864,7 @@ static int VHelp(Draw_Interpretor& di, Standard_Integer , const char** )
   return 0;
 }
 
-#ifdef WNT
+#ifdef _WIN32
 
 static Standard_Boolean Ppick = 0;
 static Standard_Integer Pargc = 0;
@@ -2489,7 +2489,7 @@ static void OSWindowSetup()
   XSynchronize(aDisplay, 0);
 
 #else
-  // WNT
+  // _WIN32
 #endif
 
 }
@@ -4202,8 +4202,8 @@ static int VGraduatedTrihedron (Draw_Interpretor& /*theDi*/, Standard_Integer th
 static int VPrintView (Draw_Interpretor& di, Standard_Integer argc,
                        const char** argv)
 {
-#ifndef WNT
-  di << "Printing implemented only for wnt!\n";
+#ifndef _WIN32
+  di << "Printing implemented only for WNT!\n";
   return 0;
 #else