https://bugs.gentoo.org/519450

--- spek-0.8.3/src/spek-fft.cc
+++ spek-0.8.3/src/spek-fft.cc
@@ -17,6 +17,7 @@
  */
 
 #include <math.h>
+#include <stdlib.h>
 
 #define __STDC_CONSTANT_MACROS
 extern "C" {
--- spek-0.8.3/src/spek-events.cc
+++ spek-0.8.3/src/spek-events.cc
@@ -16,6 +16,7 @@
  * along with Spek.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdlib.h>
 #include "spek-events.h"
 
 //IMPLEMENT_DYNAMIC_CLASS(SpekHaveSampleEvent, wxEvent)