Fix updater binary for 7.0

Note: updater is currently not backwards compatible with older trees. Maybe
later...

Change-Id: I3c2a5ef69cfa9005502408f7054e3096a64ba34b
diff --git a/mtdutils/mtdutils.h b/mtdutils/mtdutils.h
index 6cbf37e..235cbe7 100644
--- a/mtdutils/mtdutils.h
+++ b/mtdutils/mtdutils.h
@@ -19,6 +19,10 @@
 
 #include <sys/types.h>  // for size_t, etc.
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct MtdPartition MtdPartition;
 
 int mtd_scan_partitions(void);
@@ -58,4 +62,8 @@
     char *name;
 };
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif  // MTDUTILS_H_