Missing include of string.h for memset in spf_utils.c

[pjfordham]

No description provided.

[pjfordham]

found as part of https://fedoraproject.org/wiki/Toolchain/PortingToModernC effort.

Fixed with following patch:

diff --git a/src/libspf2/spf_utils.c b/src/libspf2/spf_utils.c
index 54878fa..892cea5 100644
--- a/src/libspf2/spf_utils.c
+++ b/src/libspf2/spf_utils.c
@@ -25,6 +25,9 @@
#include <memory.h>
#endif

+#ifdef HAVE_STRING_H
+# include <string.h> /* memset */
+#endif

#include "spf.h"