Merge commit '4f4e96655625a0ad8c5fc451c5a3a8dda3bf5456' as 'shared/c-rbtree'

Imported c-rbtree code with command:

  git subtree add --prefix shared/c-rbtree git@github.com:c-util/c-rbtree.git bf627e0c32241915108f66ad9738444e4d045b45 --squash

To update the library use:

  git subtree pull --prefix shared/c-rbtree git@github.com:c-util/c-rbtree.git master --squash

shared/c-rbtree/src/test-misc.c

@@ -0,0 +1,66 @@
+/*
+ * Tests for Miscellaneous Tree Operations
+ * This test contains all of the minor tests that did not fit anywhere else.
+ */
+
+#undef NDEBUG
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "c-rbtree.h"
+#include "c-rbtree-private.h"
+
+static void insert(CRBTree *t, CRBNode *n) {
+        CRBNode **i, *p;
+
+        assert(t);
+        assert(n);
+        assert(!c_rbnode_is_linked(n));
+
+        i = &t->root;
+        p = NULL;
+        while (*i) {
+                p = *i;
+                if (n < *i) {
+                        i = &(*i)->left;
+                } else {
+                        assert(n > *i);
+                        i = &(*i)->right;
+                }
+        }
+
+        c_rbtree_add(t, p, i, n);
+}
+
+static void test_move(void) {
+        CRBTree t1 = C_RBTREE_INIT, t2 = C_RBTREE_INIT;
+        CRBNode n[128];
+        unsigned int i;
+
+        for (i = 0; i < sizeof(n) / sizeof(*n); ++i) {
+                n[i] = (CRBNode)C_RBNODE_INIT(n[i]);
+                insert(&t1, &n[i]);
+        }
+
+        assert(!c_rbtree_is_empty(&t1));
+        assert(c_rbtree_is_empty(&t2));
+
+        c_rbtree_move(&t2, &t1);
+
+        assert(c_rbtree_is_empty(&t1));
+        assert(!c_rbtree_is_empty(&t2));
+
+        while (t2.root)
+                c_rbnode_unlink(t2.root);
+
+        assert(c_rbtree_is_empty(&t1));
+        assert(c_rbtree_is_empty(&t2));
+}
+
+int main(int argc, char **argv) {
+        test_move();
+
+        return 0;
+}