turn recovery into a C++ binary

Change-Id: I423a23581048d451d53eef46e5f5eac485b77555
diff --git a/roots.h b/roots.h
index cf59bfd..8abe18f 100644
--- a/roots.h
+++ b/roots.h
@@ -19,6 +19,10 @@
 
 #include "common.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // Load and parse volume data from /etc/recovery.fstab.
 void load_volume_table();
 
@@ -38,4 +42,8 @@
 // it is mounted.
 int format_volume(const char* volume);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif  // RECOVERY_ROOTS_H_