Here's a fix for this build issue. Note that there are different ways to solve this, depending on which compilers / C standards you want to support. There's a really good description at https://gcc.gnu.org/onlinedocs/cpp/Variadic-Macros.html
Martin -- Martin Michlmayr Linux for HP Helion OpenStack, Hewlett-Packard
diff -urN a/libspf2-1.2.10/debian/patches/gcc5-build-fix.patch libspf2-1.2.10/debian/patches/gcc5-build-fix.patch --- libspf2-1.2.10/debian/patches/gcc5-build-fix.patch 1970-01-01 00:00:00.000000000 +0000 +++ libspf2-1.2.10/debian/patches/gcc5-build-fix.patch 2015-06-25 13:03:52.310239946 +0000 @@ -0,0 +1,12 @@ + +--- a/src/include/spf_log.h 2015-06-25 13:00:51.866236212 +0000 ++++ b/src/include/spf_log.h 2015-06-25 13:01:11.838236625 +0000 +@@ -63,7 +63,7 @@ + #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_debugf(format, ... ) SPF_debugx( __FILE__, __LINE__, format, #__VA_ARGS__ ) + + #elif defined( __GNUC__ ) + diff -urN a/libspf2-1.2.10/debian/patches/series libspf2-1.2.10/debian/patches/series --- libspf2-1.2.10/debian/patches/series 2014-10-12 19:15:29.000000000 +0000 +++ libspf2-1.2.10/debian/patches/series 2015-06-25 13:03:58.486240074 +0000 @@ -1,2 +1,3 @@ spf_dns-include-std-headers.patch abolish-spf-rrtype.patch +gcc5-build-fix.patch