Fix linux build

Author: electricbrass

tests/unit-tests/src/teststubs.cpp

@@ -855,4 +855,12 @@ dyncolormap_t *GetSpecialLights (int lr, int lg, int lb, int fr, int fg, int fb)
 	return colormap;
 }
 
+void R_RotatePoint(fixed_t x, fixed_t y, angle_t ang, fixed_t &tx, fixed_t &ty)
+{
+	int index = ang >> ANGLETOFINESHIFT;
+
+	tx = FixedMul(x, finecosine[index]) - FixedMul(y, finesine[index]);
+	ty = FixedMul(x, finesine[index]) + FixedMul(y, finecosine[index]);
+}
+
 VERSION_CONTROL (test_stubs_cpp, "$Id$")