delphi-search-path

delphi-search-path is a variable defined in `opascal.el'.
Its value is

"."

• This variable is an alias for `opascal-search-path'.
• This variable is obsolete since 24.4;
  use `opascal-search-path' instead.

Documentation:
Directories to search when finding external units.
It is a list of directory strings. If only a single directory,
it can be a single string instead of a list. If a directory
ends in "..." then that directory is recursively searched.

You can customize this variable.