Add support for S390x system emulation

Let's enable the basics for system emulation so we can run virtual machines
with KVM!

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target-s390x/exec.h b/target-s390x/exec.h
index 5198359..13dc7dd 100644
--- a/target-s390x/exec.h
+++ b/target-s390x/exec.h
@@ -22,9 +22,14 @@
 
 register struct CPUS390XState *env asm(AREG0);
 
+#include "config.h"
 #include "cpu.h"
 #include "exec-all.h"
 
+#if !defined(CONFIG_USER_ONLY)
+#include "softmmu_exec.h"
+#endif /* !defined(CONFIG_USER_ONLY) */
+
 static inline int cpu_has_work(CPUState *env)
 {
     return env->interrupt_request & CPU_INTERRUPT_HARD; // guess