add missing include

Signed-off-by: Kim Kulling <[email protected]>

contrib/openddlparser/code/OpenDDLParser.cpp

@@ -26,6 +26,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <iostream>
 #include <sstream>
 #include <algorithm>
+#include <math.h>
 
 #ifdef _WIN32
 #  include <windows.h>