Linking the head stage2 compiler on PPC has been failing since about the 5th of April, with the following message:

ld warning: atom sorting error for 
  _ghczm6zi11zi20090527_LibFFI_Czuffizucif_closure_tbl and
  _ghczm6zi11zi20090527_LibFFI_Czuffizutype_closure_tbl 
   in compiler/stage2/build/LibFFI.o
ld warning: atom sorting error for
  _ghczm6zi11zi20090527_LibFFI_Czuffizucif_closure_tbl and
  _ghczm6zi11zi20090527_LibFFI_Czuffizutype_closure_tbl 
  in compiler/stage2/build/LibFFI.o
ld: scattered reloc r_address too large for inferred architecture ppc

From the build bot logs, it was working on the 4th of April. Coincidently, a stack of Cmm codegen patches were also pushed that day...