cann't find the gdbm

[dj]

hello,
    when I install sqwebmail-3.2.0, it gave me some information below

        checking for gdbm_open in -lgdbm... no
        checking for gdbm_open... no
        checking for dbopen in -ldb... no
        checking for db_open in -ldb... no
        checking for db_env_create in -ldb... no
        checking for dbopen... no
        checking for db_open... no
        checking for db_env_create... no
        configure: error: Cannot find either the gdbm or the db library.

     but I had already installed gdbm-1.8.0 successfully before. the "make 
install" tell me :

        Libraries have been installed in:
           /usr/local/lib

        To link against installed libraries in a given directory, LIBDIR,
        you must use the `-LLIBDIR' flag during linking.

         You will also need to do one of the following:
           - add LIBDIR to the `LD_LIBRARY_PATH' environment variable
             during execution
           - use the `-RLIBDIR' linker flag

    why sqwebmail cann't find the gdbm.