validate fails on MacOS

[Manuel M T Chakravarty]

/Users/chak/Code/ghc-test/ghc/stage1-inplace/ghc  -Werror -H64m -O0 - 
fasm  -I../includes -I. -Iparallel -Ism -DCOMPILING_RTS -package-name  
rts -static  -I../gmp/gmpbuild -I../libffi/build/include -I. -dcmm- 
lint  -hisuf debug_hi -hcsuf debug_hc -osuf debug_o -optc-DDEBUG   -c  
PrimOps.cmm -o PrimOps.debug_o
cc1: warnings being treated as e/Users/chak/Code/ghc-test/ghc/stage1- 
inplace/ghc  -Werror -H64m -O0 -fasm  -I../includes -I. -Iparallel - 
Ism -DCOMPILING_RTS -package-name rts -static  -I../gmp/gmpbuild -I../ 
libffi/build/include -I. -dcmm-lint  -hisuf debug_hi -hcsuf debug_hc - 
osuf debug_o -optc-DDEBUG   -c StgMiscClosures.cmm -o  
StgMiscClosures.debug_o
rrors
sm/Scav.c: In function 'scavengeTSO':

sm/Scav.c:72:0:
      warning: format '%d' expects type 'int', but argument 3 has type  
'StgThreadID'
/Users/chak/Code/ghc-test/ghc/stage1-inplace/ghc  -Werror -H64m -O0 - 
fasm  -I../includes -I. -Iparallel -Ism -DCOMPILING_RTS -package-name  
rts -static  -I../gmp/gmpbuild -I../libffi/build/include -I. -dcmm- 
lint  -hisuf debug_hi -hcsuf debug_hc -osuf debug_o -optc-DDEBUG   -c  
StgStartup.cmm -o StgStartup.debug_o
make[2]: *** [sm/Scav.debug_o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [all] Error 1
make: *** [stage1] Error 2