This function locates the terminfo file for name, then calls "unibi_from_file".
It looks in the following places:
1. If the environment variable "TERMINFO" is set, it is interpreted as the name of the directory to
search for local terminal definitions before checking in the standard place.
2. Otherwise, "$HOME/.terminfo" is tried.
3. If that was not successful and "TERMINFO_DIRS" is set, it is interpreted as a colon-separated list of
directories to search.
4. If "TERMINFO_DIRS" is not set, a compiled-in fallback ("unibi_terminfo_dirs") is used instead.