package.install does not respect --exec-prefix

[pust@…]

i believe that setting --exec-prefix should cause bindir to be

$(exec-locate)/bin

and libdir to be

$(exec-locate)/lib.

72c72
<     local bin-locate = [ option.get bindir : $(prefix)/bin ] ;
---
>     local bin-locate = [ option.get bindir : $(exec-locate)/bin ] ;
75c75
<     local lib-locate = [ option.get libdir : $(prefix)/lib ] ;
---
>     local lib-locate = [ option.get libdir : $(exec-locate)/lib ] ;