https://github.com/shevek/libspf2/issues/13
https://bugs.gentoo.org/show_bug.cgi?id=570486

Index: libspf2-1.2.10/src/include/spf_log.h
===================================================================
--- libspf2-1.2.10/src/include/spf_log.h
+++ libspf2-1.2.10/src/include/spf_log.h    2015-10-20 23:23:04.579055906 +0200
@@ -60,10 +60,10 @@

 #if defined( __STDC_VERSION__ ) && __STDC_VERSION__ >= 199901L

-#define SPF_errorf(format, ... ) SPF_errorx( __FILE__, __LINE__, format, __VA_ARGS__ )
-#define SPF_warningf(format, ... ) SPF_warningx( __FILE__, __LINE__, format, __VA_ARGS__ )
-#define SPF_infof(format, ... ) SPF_infox( __FILE__, __LINE__, format, __VA_ARGS__ )
-#define SPF_debugf(format, ... ) SPF_debugx( __FILE__, __LINE__, format, __VA_ARGS__ )
+#define SPF_errorf(...) SPF_errorx( __FILE__, __LINE__, __VA_ARGS__ )
+#define SPF_warningf(...) SPF_warningx( __FILE__, __LINE__, __VA_ARGS__ )
+#define SPF_infof(...) SPF_infox( __FILE__, __LINE__, __VA_ARGS__ )
+#define SPF_debugf(...) SPF_debugx( __FILE__, __LINE__, __VA_ARGS__ )

 #elif defined( __GNUC__ )