validate problems with Arrow.hi

[Manuel M T Chakravarty]

When validating on MacOS 10.5, I get the following test failures

Unexpected failures:
    arrow(normal)
    arrowapply1(normal)
    arrowapply2(normal)
    arrowapply3(normal)
    arrowapply4(normal)
    arrowapply5(normal)
    arrowcase1(normal)
    arrowdo1(normal)
    arrowdo2(normal)
    arrowfail001(normal)
    arrowform1(normal)
    arrowif1(normal)
    arrowlet1(normal)
    arrowrec1(normal)
    arrowrun001(normal)
    arrowrun003(normal)
    tc192(normal)

Everything with arrows fails as the Arrow.hi file can't be loaded; ie,  
I get

arrowapply1.hs:8:4:
     Can't find interface-file declaration for variable  
Control.Arrow.>>>
       Probable cause: bug in .hi-boot file, or inconsistent .hi file
       Use -ddump-if-trace to get an idea of which file caused the error
     In the expression: proc (x, y, z) -> returnA -< x + y
     In the definition of `f': f = proc (x, y, z) -> returnA -< x + y

This shouldn't be OS-specific, so I wonder what's happening.

Manuel