fix win compile

contrib/Netgen/README.txt

 
 This directory contains Joachim Sch\"oberl's NETGEN mesh generator:
 
-- the libsrc and nglib directories are unmodified copies taken from 
+The libsrc and nglib directories are unmodified copies taken from 
+
   svn co https://netgen-mesher.svn.sourceforge.net/svnroot/netgen-mesher
-  (SVN rev. 469)
 
-- the nglib_gmsh.cpp file replaces the original nglib/nglib.cpp file
+(SVN rev. 469), with the following exceptions:
+
+* dllexport/dllimport directives have been removed from nglib/nglib.h
+* nglib_gmsh.cpp file replaces the original nglib/nglib.cpp file
 
 See the LICENSE file for license information.

contrib/Netgen/nglib/nglib.h

@@ -23,7 +23,8 @@
 
 // Philippose - 14.02.2009
 // Modifications for creating a DLL in Windows
-#ifdef WIN32
+//#ifdef WIN32
+#if 0 // for GMSH
    #ifdef NGLIB_EXPORTS || nglib_EXPORTS
       #define DLL_HEADER   __declspec(dllexport)
    #else