ptrace: print data argument of PTRACE_SINGLEBLOCK et al requests as signo

* process.c (SYS_FUNC(ptrace)): Print data argument of
PTRACE_SINGLEBLOCK, PTRACE_SYSEMU, and PTRACE_SYSEMU_SINGLESTEP requests
as a signal number.
diff --git a/process.c b/process.c
index 520711b..b61d354 100644
--- a/process.c
+++ b/process.c
@@ -167,9 +167,20 @@
 			break;
 #endif
 		case PTRACE_CONT:
-		case PTRACE_SINGLESTEP:
-		case PTRACE_SYSCALL:
 		case PTRACE_DETACH:
+		case PTRACE_SYSCALL:
+#ifdef PTRACE_SINGLESTEP
+		case PTRACE_SINGLESTEP:
+#endif
+#ifdef PTRACE_SINGLEBLOCK
+		case PTRACE_SINGLEBLOCK:
+#endif
+#ifdef PTRACE_SYSEMU
+		case PTRACE_SYSEMU:
+#endif
+#ifdef PTRACE_SYSEMU_SINGLESTEP
+		case PTRACE_SYSEMU_SINGLESTEP:
+#endif
 			printsignal(data);
 			break;
 		case PTRACE_SETOPTIONS: