--- ./testsuite/TestSuiteUtils.cpp
+++ ./testsuite/TestSuiteUtils.cpp
@@ -39,7 +39,7 @@
 #elif defined(_WIN32)
 #define USE_WIN32
 #else //_WIN32
-#error Unknown system
+#define USE_POSIX
 #endif //POSIX
 
 #include <Inventor/errors/SoDebugError.h>
