Initialize x->attr in yxml_init()

Shouldn't really matter to any application that respected the
documentation, but it's better than leaving it uninitialized.
diff --git a/yxml.c b/yxml.c
index 4f9f1b4..4582509 100644
--- a/yxml.c
+++ b/yxml.c
@@ -327,7 +327,7 @@
 	x->stack = stack;
 	x->stacksize = stacksize;
 	*x->stack = 0;
-	x->elem = x->pi = (char *)x->stack;
+	x->elem = x->pi = x->attr = (char *)x->stack;
 	x->state = YXMLS_init;
 }
 
diff --git a/yxml.c.in b/yxml.c.in
index 4cc40a8..8d40bc0 100644
--- a/yxml.c.in
+++ b/yxml.c.in
@@ -263,7 +263,7 @@
 	x->stack = stack;
 	x->stacksize = stacksize;
 	*x->stack = 0;
-	x->elem = x->pi = (char *)x->stack;
+	x->elem = x->pi = x->attr = (char *)x->stack;
 	x->state = YXMLS_init;
 }