Add include of signal.h to Emulator.cpp

ndb/src/kernel/vm/Emulator.cpp:
  Added signal.h to include header for signal

ndb/src/kernel/vm/Emulator.cpp

@@ -35,6 +35,8 @@
 #include <NdbSleep.h>
 #include <new>
 
+#include <signal.h>        // For process signals
+
 extern "C" {
   extern void (* ndb_new_handler)();
 }