diff --git a/src/Lib/Optimize/genfans.cxx b/src/Lib/Optimize/genfans.cxx
index 07ab8596..166c3542 100644
--- a/src/Lib/Optimize/genfans.cxx
+++ b/src/Lib/Optimize/genfans.cxx
@@ -24,6 +24,7 @@
 #include <simgear/compiler.h>
 
 #include <iostream>
+#include <stdlib.h>
 
 #include "genfans.hxx"
 
diff --git a/src/Lib/Polygon/polygon.hxx b/src/Lib/Polygon/polygon.hxx
index a2c56cfe..d0d45eb2 100644
--- a/src/Lib/Polygon/polygon.hxx
+++ b/src/Lib/Polygon/polygon.hxx
@@ -32,6 +32,7 @@
 
 #include <simgear/compiler.h>
 #include <simgear/math/sg_types.hxx>
+#include <simgear/math/point3d.hxx>
 
 #include <iostream>
 #include <string>