bdb: disable Werror for format-security

This is causing build failures in some build environments, like NixOS.
I don't think we are going to patch bdb at this point, and this warning
has existed for as long as we've used bdb.

Fixes #25211.

Tested (in Docker) with:
```bash
docker run -it nixos/nix
nix-shell -p gitMinimal gcc12 libtool pkg-config curl gnumake patch autoconf automake
git clone https://github.com/bitcoin/bitcoin
make -C bitcoin/depends bdb
```

Co-authored-by: Ryan Ofsky <[email protected]>

Author: fanquake

depends/packages/bdb.mk

@@ -14,7 +14,7 @@ $(package)_config_opts_freebsd=--with-pic
 $(package)_config_opts_netbsd=--with-pic
 $(package)_config_opts_openbsd=--with-pic
 $(package)_config_opts_android=--with-pic
-$(package)_cflags+=-Wno-error=implicit-function-declaration
+$(package)_cflags+=-Wno-error=implicit-function-declaration -Wno-error=format-security
 $(package)_cppflags_mingw32=-DUNICODE -D_UNICODE
 endef