Fix compiling on MSVC; patch #955 by Buginator, slightly modified by me

git-svn-id: svn+ssh://svn.gna.org/svn/warzone/trunk@3607 4a71c877-e1ca-e34f-864e-861f7616d084

lib/framework/trig.h

@@ -17,12 +17,16 @@
 	along with Warzone 2100; if not, write to the Free Software
 	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
-/*! \file trig.h
+/** \file
  *  * \brief Interface to trig lookup tables
  */
+
 #ifndef _trig_h
 #define _trig_h
 
+#include "frame.h"
+#include "math-help.h"
+
 /* The number of units around a full circle */
 #define TRIG_DEGREES	360
 

src/difficulty.c

@@ -31,6 +31,7 @@
 #include "lib/framework/frame.h"
 
 #include <math.h>
+#include "lib/framework/math-help.h"
 
 #include "difficulty.h"
 // ------------------------------------------------------------------------------------