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/LDOM/LDOMBasicString.cxx

@@ -317,7 +317,7 @@ Standard_Boolean LDOMBasicString::GetInteger (Standard_Integer& aResult) const
 }
 
 #ifdef OCCT_DEBUG
-#ifndef WNT
+#ifndef _MSC_VER
 //=======================================================================
 // Debug Function for DBX: use "print -p <Variable> or pp <Variable>"
 //=======================================================================

src/LDOM/LDOMParser.cxx

@@ -26,7 +26,7 @@
 #include <TCollection_ExtendedString.hxx>
 
 #include <fcntl.h>
-#ifdef WNT
+#ifdef _MSC_VER
 #include <io.h>
 #else
 #include <unistd.h>
@@ -63,7 +63,7 @@ inline
 #ifdef LDOM_PARSER_TRACE
   static FILE * ff = NULL;
   TCollection_AsciiString aTraceFileName;
-#ifdef WNT
+#ifdef _WIN32
   aTraceFileName = TCollection_AsciiString (getenv("TEMP")) + "\\ldom.trace";
 #else
   aTraceFileName = "/tmp/ldom.trace";

src/LDOM/LDOM_BasicNode.cxx

@@ -45,7 +45,7 @@ const LDOM_BasicNode * LDOM_BasicNode::GetSibling () const
 }
 
 #ifdef OCCT_DEBUG
-#ifndef WNT
+#ifndef _MSC_VER
 //=======================================================================
 // Debug Function for DBX: use "print -p <Variable> or pp <Variable>"
 //=======================================================================

src/LDOM/LDOM_XmlReader.cxx

@@ -25,7 +25,7 @@
 
 #include <string.h>
 #include <errno.h>
-#ifdef WNT
+#ifdef _MSC_VER
 #include <io.h>
 #else
 #include <unistd.h>

src/LDOM/LDOM_XmlWriter.cxx

@@ -409,7 +409,7 @@ LDOM_XmlWriter& LDOM_XmlWriter::operator<<     (const LDOM_Node& theNodeToWrite)
       break;
     }
   default:
-#ifndef WNT
+#ifndef _MSC_VER
       cerr << "Unrecognized node type = "
         << (long)theNodeToWrite.getNodeType() << endl
 #endif