Index: src/lib/base/String.h
--- src/lib/base/String.h.orig
+++ src/lib/base/String.h
@@ -32,7 +32,7 @@ std::string format(const char *fmt, ...);
 /*!
 Same as format() except takes va_list.
 */
-std::string vformat(const char *fmt, va_list);
+std::string vformat(const char *fmt, __va_list);
 
 //! Print a string using sprintf-style formatting
 /*!
