diff --git a/Foundation/src/Semaphore.cpp b/Foundation/src/Semaphore.cpp
index c6fa7b119..031b6eb96 100644
--- a/Foundation/src/Semaphore.cpp
+++ b/Foundation/src/Semaphore.cpp
@@ -39,6 +39,8 @@
 
 #if defined(POCO_OS_FAMILY_WINDOWS)
 #include "Semaphore_WIN32.cpp"
+#elif defined(POCO_VXWORKS)
+#include "Semaphore_VX.cpp"
 #else
 #include "Semaphore_POSIX.cpp"
 #endif
diff --git a/Foundation/src/SharedMemory.cpp b/Foundation/src/SharedMemory.cpp
index baa436074..7320ed7b5 100644
--- a/Foundation/src/SharedMemory.cpp
+++ b/Foundation/src/SharedMemory.cpp
@@ -33,10 +33,8 @@
 // DEALINGS IN THE SOFTWARE.
 //
 
-#include "Poco/Platform.h"
 
-
-#if POCO_OS == POCO_OS_SOLARIS
+#if defined(__sun)
 #undef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 500
 #endif
diff --git a/Foundation/src/SignalHandler.cpp b/Foundation/src/SignalHandler.cpp
index 06447ffd9..9abc54625 100644
--- a/Foundation/src/SignalHandler.cpp
+++ b/Foundation/src/SignalHandler.cpp
@@ -37,7 +37,7 @@
 #include "Poco/SignalHandler.h"
 
 
-#if defined(POCO_OS_FAMILY_UNIX)
+#if defined(POCO_OS_FAMILY_UNIX) && !defined(POCO_VXWORKS)
 
 
 #include "Poco/Thread.h"