turn recovery into a C++ binary

Change-Id: I423a23581048d451d53eef46e5f5eac485b77555
diff --git a/bootloader.h b/bootloader.h
index 2e749aa..712aa1a 100644
--- a/bootloader.h
+++ b/bootloader.h
@@ -17,6 +17,10 @@
 #ifndef _RECOVERY_BOOTLOADER_H
 #define _RECOVERY_BOOTLOADER_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Bootloader Message
  *
  * This structure describes the content of a block in flash
@@ -47,4 +51,8 @@
 int get_bootloader_message(struct bootloader_message *out);
 int set_bootloader_message(const struct bootloader_message *in);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif