poco: propagate dependencies imported by CMake scripts

This also requires enable multiple outputs to prevent the closure size from
increasing.

pkgs/development/libraries/poco/default.nix

···
 
   nativeBuildInputs = [ cmake pkg-config ];
 
-  buildInputs = [ zlib pcre expat sqlite openssl unixODBC libmysqlclient ];
+  buildInputs = [ openssl unixODBC libmysqlclient ];
+  propagatedBuildInputs = [ zlib pcre expat sqlite ];
+
+  outputs = [ "out" "dev" ];
 
   MYSQL_DIR = libmysqlclient;
   MYSQL_INCLUDE_DIR = "${MYSQL_DIR}/include/mysql";