$> make
[  0%] Building C object CMakeFiles/micropy_extmod_btree.dir/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c.o
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c: In function '__bt_close':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c:60:1: warning: old-style function definition [-Wold-style-definition]
   60 | __bt_close(dbp)
      | ^~~~~~~~~~
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c: In function '__bt_sync':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c:113:1: warning: old-style function definition [-Wold-style-definition]
  113 | __bt_sync(dbp, flags)
      | ^~~~~~~~~
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_close.c: In function 'bt_meta':
/home/hoedurgit/micropython/lib/berkeley-db-1.xx/btree/bt_close.c:156:1: warning: old-style function definition [-Wold-style-definition]
  156 | bt_meta(t)
      | ^~~~~~~
[  0%] Building C object CMakeFiles/micropy_extmod_btree.dir/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c.o
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c: In function '__bt_pgin':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c:58:1: warning: old-style function definition [-Wold-style-definition]
   58 | __bt_pgin(t, pg, pp)
      | ^~~~~~~~~
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c: In function '__bt_pgout':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c:126:1: warning: old-style function definition [-Wold-style-definition]
  126 | __bt_pgout(t, pg, pp)
      | ^~~~~~~~~~
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c: In function 'mswap':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_conv.c:200:1: warning: old-style function definition [-Wold-style-definition]
  200 | mswap(pg)
      | ^~~~~
[  1%] Building C object CMakeFiles/micropy_extmod_btree.dir/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_debug.c.o
[  1%] Building C object CMakeFiles/micropy_extmod_btree.dir/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_delete.c.o
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_delete.c: In function '__bt_delete':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_delete.c:60:1: warning: old-style function definition [-Wold-style-definition]
   60 | __bt_delete(dbp, key, flags)
      | ^~~~~~~~~~~
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_delete.c: In function '__bt_stkacq':
/home/hoedur/git/micropython/lib/berkeley-db-1.xx/btree/bt_delete.c:141:1: warning: old-style function definition [-Wold-style-definition]
  141 | __bt_stkacq(t, hp, c)
      | ^~~~~~~~~~~
[...]