Expose per arch headers.

Bug: 73013352

Test: Compiles.
Change-Id: Ic05660db7d7858a9857143ee5e58cdaddcf52a35
diff --git a/libunwindstack/RegsX86_64.cpp b/libunwindstack/RegsX86_64.cpp
index 70921f8..0f66943 100644
--- a/libunwindstack/RegsX86_64.cpp
+++ b/libunwindstack/RegsX86_64.cpp
@@ -19,13 +19,12 @@
 #include <functional>
 
 #include <unwindstack/Elf.h>
+#include <unwindstack/MachineX86_64.h>
 #include <unwindstack/MapInfo.h>
 #include <unwindstack/Memory.h>
 #include <unwindstack/RegsX86_64.h>
-
-#include "MachineX86_64.h"
-#include "UcontextX86_64.h"
-#include "UserX86_64.h"
+#include <unwindstack/UcontextX86_64.h>
+#include <unwindstack/UserX86_64.h>
 
 namespace unwindstack {