Fix two issues detected by Flössie

rtengine/imagedata.cc

@@ -857,8 +857,7 @@ bool FramesData::hasIPTC (unsigned int frame) const
 tm FramesData::getDateTime (unsigned int frame) const
 {
     if (frames.empty() || frame >= frames.size() ) {
-        tm emptytm = {0, 0, 0, 0, 0, 0, 0, 0, 0};
-        return emptytm;
+        return {};
     } else {
         return frames.at(frame)->getDateTime ();
     }

rtengine/labimage.cc

@@ -17,9 +17,11 @@
  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "labimage.h"
+#include <cstring>
 #include <memory>
 
+#include "labimage.h"
+
 namespace rtengine
 {