* environ.cc (env_win32_to_posix_path_list): Declare.

* environ.cc (env_win32_to_posix_path_list): Declare.
(conv_envvars): Use env_win32_to_posix_path_list rather than
cygwin_win32_to_posix_path_list.
(posify): Translate back to win32 path if errno is EIDRM.
* environ.h: Update copyright.  Define ENV_CVT.
* path.cc (conv_path_list): If converting for the environment and removed an
element set errno to ENV_CVT.
(env_win32_to_posix_path_list): New function.