Include <rpm/rpmstring.h> for the rasprintf function prototype, to
avoid an implicit function declaration.  Improves compatibility with
future compilers.

diff --git a/src/xml_file.c b/src/xml_file.c
index e369f5170f181758..d74af230081fb3d0 100644
--- a/src/xml_file.c
+++ b/src/xml_file.c
@@ -20,6 +20,7 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 #include <assert.h>
+#include <rpm/rpmstring.h>
 #include "xml_file.h"
 #include <errno.h>
 #include "error.h"