Makefile notdir funnction无法正常工作

Question

PROGRAMS =  programs/aes/aescrypt2      programs/aes/crypt_and_hash \
programs/hash/hello     programs/hash/generic_sum   \
programs/hash/md5sum        programs/hash/sha1sum       \
programs/hash/sha2sum       programs/pkey/dh_client     \
programs/pkey/dh_genprime   programs/pkey/dh_server     \
programs/pkey/gen_key                       \
programs/pkey/key_app       programs/pkey/key_app_writer    \
programs/pkey/mpi_demo      programs/pkey/pk_decrypt        \
programs/pkey/pk_encrypt        programs/pkey/pk_sign       \
programs/pkey/pk_verify     programs/pkey/rsa_genkey        \
programs/pkey/rsa_decrypt   programs/pkey/rsa_encrypt   \
programs/pkey/rsa_sign      programs/pkey/rsa_verify        \
programs/pkey/rsa_sign_pss  programs/pkey/rsa_verify_pss    \
programs/ssl/ssl_client1        programs/ssl/ssl_client2        \
programs/ssl/ssl_server     programs/ssl/ssl_server2        \
programs/ssl/ssl_fork_server    programs/ssl/mini_client        \
programs/ssl/ssl_mail_client    programs/random/gen_entropy \
programs/random/gen_random_havege               \
programs/random/gen_random_ctr_drbg             \
programs/test/ssl_cert_test programs/test/benchmark     \
programs/test/selftest      programs/test/ssl_test      \
programs/util/pem2der       programs/util/strerror      \
programs/x509/cert_app      programs/x509/crl_app       \
programs/x509/cert_req

.SILENT:
pod:
    for i in $(PROGRAMS);                   \
    do                                      \
        echo $(notdir $${i});                       \
    done;

我已经从我的一个makefile中发布了一个示例，在上面的代码中，notdir函数没有按预期工作，有人可以帮助我，我在这里缺少什么吗？