[EDIT: I deleted my previous posts because wrong compilation]
Yep, that works, even in objpas mode:
unit test;
{$IFDEF FPC}{$MODE objpas}{$H+}{$ENDIF}
interface
uses
bgrabitmap in '/home/fred/bgrabitmap-dev-bgrabitmap/bgrabitmap/bgrabitmap.pas', ...
OK and excellent.
By the way I will not be against:
uses
mayunit in '/my/directory/';