test_atomic and test_spinlock requires daemon option

building without daemon option results two errors :

/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: contrib/test_atomic.o: in function `thread_set':
test_atomic.c:(.text+0x19): undefined reference to `dt_get_id'
/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: contrib/test_atomic.o: in function `thread_xchg':
test_atomic.c:(.text+0x90): undefined reference to `dt_get_id'
/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: contrib/test_atomic.o: in function `main':
test_atomic.c:(.text.startup+0x7c): undefined reference to `dt_create'
[...]
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:1630: contrib/test_atomic] Error 1

/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: contrib/test_spinlock.o: in function `main':
test_spinlock.c:(.text.startup+0x71): undefined reference to `dt_create'
/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: test_spinlock.c:(.text.startup+0x7e): undefined reference to `dt_start'
/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: test_spinlock.c:(.text.startup+0x88): undefined reference to `dt_join'
/usr/lib/gcc/x86_64-pc-linux-gnu/14/../../../../x86_64-pc-linux-gnu/bin/ld: test_spinlock.c:(.text.startup+0x92): undefined reference to `dt_delete'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:1702: contrib/test_spinlock] Error 1

Indeed, these tests call this "daemon" header file knot/server/dthreads.h.

closed via commit 3efd85c9

mentioned in commit 3efd85c9

mentioned in commit d32ce974