diff --git a/src/files/files.h b/src/files/files.h
index 7b53cb16..27cc9c54 100644
--- a/src/files/files.h
+++ b/src/files/files.h
@@ -1,7 +1,9 @@
 #ifndef FILES_FILES_H_
 #define FILES_FILES_H_
 
+#ifndef std::string
 #include <string>
+#endif
 
 extern bool write_binary_file(std::string filename, const char* data, size_t size);
 extern unsigned int append_binary_file(std::string filename, const char* data, size_t size);