uClinux uc-libc build error : crypt

其實這個以前Chris就解決過了，但是...還是google了一次：
根據這一篇 http://mailman.uclinux.org/pipermail/uclinux-dev/2005-February/030843.html
說明，是因為uc-libc用crypt_old而不是crypt的關係，所以要修改發生error的makefile，把link object的crypt改為crypt_old

1. Edit lib/Makefile and force it to traverse libcrypt_old, at or about
line 31, add to dir_y so that it becomes:

   ifeq ($(LIBCDIR),libc)
      dir_y += libm libcrypt_old
   endif

2. Enable crypt_old in the user config (should be near "login" in
core apps). You may need to have "login" enable to be able to
enable this, I don't recall right now.

3. Check in vendors/config/common/config.arch that libcrypt_old is
included in linker flags when CONFIG_LIB_LIBCRYPT_OLD is enabled.