Release v1.5.2 on 2021-09-24.

1. e08da97 Fix/Update copyright notices; Add SPDX annotation by Harald Welte · 7 years ago
2. 2b82c1c fix FSF address in sources/headers by Jaroslav Škarvada · 9 years ago
3. 54187ba core/rbtree: remove redundant if()-condition in rb_erase() by Sylvain Munaut · 13 years ago
4. a83cbe1 core/rbtree: make clear distinction between two different cases in rb_erase() by Sylvain Munaut · 13 years ago
5. b8c5bde core/rbtree: reorganize code in rb_erase() for additional changes by Sylvain Munaut · 13 years ago
6. 0395c6e core/rbtree: optimize rb_erase() by Sylvain Munaut · 13 years ago
7. 2179f40 core/rbtree: add const qualifier to some functions by Sylvain Munaut · 13 years ago
8. f74db0b add rb-tree implementation to libosmocore by Pablo Neira Ayuso · 13 years ago