Multiple-inclusion guard for common.h
diff --git a/common.h b/common.h
index 70e4a5a..9f1d40e 100644
--- a/common.h
+++ b/common.h
@@ -1,3 +1,6 @@
+#ifndef COMMON_H
+#define COMMON_H
+
 #if defined(HAVE_LIBUNWIND)
 #include <libunwind.h>
 #endif /* defined(HAVE_LIBUNWIND) */
@@ -274,3 +277,5 @@
 extern void arch_check_dbg(Process *proc);
 
 extern struct ltelf main_lte;
+
+#endif