Link problem on FreeBSD

GHC head on FreeBSD causes a link error if -prof and -threaded are specified:

% cat main.hs
main = putStrLn "hello"
% ghc -prof -threaded main.hs
[1 of 1] Compiling Main             ( main.hs, main.o )
/usr/local/lib/gcc47/gcc/x86_64-portbld-freebsd9.1/4.7.3/../../../../../x86_64-portbld-freebsd9.1/bin/ld: cannot find -lthr
collect2: error: ld returned 1 exit status

Note that libHSrts_thr* are certainly installed.

Trac metadata

Trac field	Value
Version	7.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
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