don't crash when header is not available (fixes synthesis.t with rpm 4.4.2.2)

(backport from HEAD)

1 files changed, 1 insertions, 1 deletions

diff --git a/URPM.xs b/URPM.xs
index 9ea14b5..4cda150 100644
--- a/URPM.xs
+++ b/URPM.xs
@@ -447,7 +447,7 @@ return_list_str(char *s, Header header, int_32 tag_name, int_32 tag_flags, int_3
 static int
 xpush_simple_list_str(Header header, int_32 tag_name) {
   dSP;
-  {
+  if (header) {
     int_32 type, c;
     char **list = NULL;
     int i;