diff -ur avl-2.0.3.orig/pavl.c avl-2.0.3/pavl.c
--- avl-2.0.3.orig/pavl.c	2007-08-26 06:40:30.000000000 +0200
+++ avl-2.0.3/pavl.c	2014-05-04 22:38:31.532117606 +0200
@@ -249,7 +249,7 @@
 {
   struct pavl_node *p; /* Traverses tree to find node to delete. */
   struct pavl_node *q; /* Parent of |p|. */
-  int dir;             /* Side of |q| on which |p| is linked. */
+  int dir = 0;             /* Side of |q| on which |p| is linked. */
 
   assert (tree != NULL && item != NULL);
 
diff -ur avl-2.0.3.orig/pbst.c avl-2.0.3/pbst.c
--- avl-2.0.3.orig/pbst.c	2007-08-26 06:40:30.000000000 +0200
+++ avl-2.0.3/pbst.c	2014-05-04 22:38:09.813269693 +0200
@@ -149,7 +149,7 @@
 {
   struct pbst_node *p; /* Traverses tree to find node to delete. */
   struct pbst_node *q; /* Parent of |p|. */
-  int dir;             /* Side of |q| on which |p| is linked. */
+  int dir = 0;             /* Side of |q| on which |p| is linked. */
 
   assert (tree != NULL && item != NULL);
 
diff -ur avl-2.0.3.orig/prb.c avl-2.0.3/prb.c
--- avl-2.0.3.orig/prb.c	2007-08-26 06:40:30.000000000 +0200
+++ avl-2.0.3/prb.c	2014-05-04 22:38:43.476033954 +0200
@@ -255,7 +255,7 @@
   struct prb_node *p; /* Node to delete. */
   struct prb_node *q; /* Parent of |p|. */
   struct prb_node *f; /* Node at which we are rebalancing. */
-  int dir;            /* Side of |q| on which |p| is a child;
+  int dir = 0;            /* Side of |q| on which |p| is a child;
                          side of |f| from which node was deleted. */
 
   assert (tree != NULL && item != NULL);
diff -ur avl-2.0.3.orig/test.c avl-2.0.3/test.c
--- avl-2.0.3.orig/test.c	2007-08-26 06:40:30.000000000 +0200
+++ avl-2.0.3/test.c	2014-05-04 22:39:50.410565069 +0200
@@ -353,6 +353,7 @@
     default:
       assert (0);
     }
+    return NULL;
 }
 
 /* Releases |block| previously returned by |mt_allocate()|. */
@@ -993,7 +994,7 @@
 int
 main (int argc, char *argv[])
 {
-  struct test_options opts;        /* Command-line options. */
+  struct test_options opts = {0};        /* Command-line options. */
   int *insert, *delete;                /* Insertion and deletion orders. */
   int success;                  /* Everything okay so far? */
 
@@ -1057,7 +1058,7 @@
       alloc = mt_create (opts.alloc_policy, opts.alloc_arg, opts.verbosity);
 
       {
-        int okay;
+        int okay = 0;
         struct libavl_allocator *a = mt_allocator (alloc);
 
         switch (opts.test)