diff --git a/3rdparty/iaxclient/lib/iaxclient.h b/3rdparty/iaxclient/lib/iaxclient.h
index 8d14afbcb..34918fa0c 100644
--- a/3rdparty/iaxclient/lib/iaxclient.h
+++ b/3rdparty/iaxclient/lib/iaxclient.h
@@ -45,6 +45,9 @@ typedef int socklen_t;
 #include <sys/socket.h>
 #endif
 
+// FlightGear modification: for FreeBSD compat
+#include <sys/time.h> // for struct timeval
+
 #ifdef BUILDING_DLL
 # if defined(WIN32) ||  defined(_WIN32_WCE)
 #  ifdef _MSC_VER
diff --git a/3rdparty/iaxclient/lib/libiax2/src/iax.c b/3rdparty/iaxclient/lib/libiax2/src/iax.c
index 5faa20581..2234b2d10 100644
--- a/3rdparty/iaxclient/lib/libiax2/src/iax.c
+++ b/3rdparty/iaxclient/lib/libiax2/src/iax.c
@@ -72,7 +72,8 @@
 #include <arpa/inet.h>
 #include <time.h>
 
-#if !defined(MACOSX) && !defined(__OpenBSD__)
+// FlightGear: Modified to include FreeBSD
+#if !defined(MACOSX) && !defined(__OpenBSD__) && !defined(__FreeBSD__)
 #include <malloc.h>
 #if !defined(SOLARIS)
 #include <error.h>
diff --git a/src/Airports/airports_fwd.hxx b/src/Airports/airports_fwd.hxx
index 6b89c0e82..a596f3db9 100644
--- a/src/Airports/airports_fwd.hxx
+++ b/src/Airports/airports_fwd.hxx
@@ -25,6 +25,7 @@
 #include <map>
 #include <vector>
 #include <string>
+#include <ctime> // for time_t
 
 // forward decls
 class FGAirport;
diff --git a/src/FDM/JSBSim/JSBSim.cxx b/src/FDM/JSBSim/JSBSim.cxx
index 9f8ed7761..91c4dd615 100644
--- a/src/FDM/JSBSim/JSBSim.cxx
+++ b/src/FDM/JSBSim/JSBSim.cxx
@@ -28,7 +28,7 @@
 #include <simgear/compiler.h>
 #include <simgear/sg_inlines.h>
 
-#include <stdio.h>    //    size_t
+#include <cstdlib>    //    size_t
 #include <string>
 
 #include <simgear/constants.h>