change NOSSE2 conditional compilation. hope it still works for gcc guys

desmume/src/matrix.cpp

@@ -33,7 +33,7 @@ void MatrixInit  (float *matrix)
 	matrix[0] = matrix[5] = matrix[10] = matrix[15] = 1.f;
 }
 
-#if not defined(WIN32) || defined(NOSSE2)
+#ifdef NOSSE2
 void MATRIXFASTCALL MatrixMultVec4x4 (const float *matrix, float *vecPtr)
 {
 	float x = vecPtr[0];

desmume/src/types.h

@@ -25,6 +25,10 @@
 #include "config.h"
 #endif
 
+#ifndef _MSC_VER
+#define NOSSE2
+#endif
+
 #define DESMUME_NAME "DeSmuME"
 
 #ifdef _WIN64