HPCC-9173 Ubuntu 13.04 Build Fails

MIssing deffintion for PRIO_PROCESS

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>

system/jlib/jthread.cpp

@@ -32,6 +32,7 @@
 #include <sys/wait.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
+#include <sys/resource.h>
 #endif
 
 #if defined(_DEBUG) && defined(_WIN32) && !defined(USING_MPATROL)