GHC 6.6.1 Build failure on plain vanilla linux i686 build

[Robin Bate Boerop]

My build dies very soon after issuing "make".  Here are the last few 
lines.  Does anyone know what is happening and how to fix it?  (The 
floating constant of which the error message speaks is 
__GHC_PATCHLEVEL__, which is set to 2.20060331.)  I have a working GHC 
6.4 installed, BTW.

/sec/bin/ghc -optc-O -optc-I. -optc-Iinclude 
-optc-D__GHC_PATCHLEVEL__=2.20060331 -optc-I../libraries/base/cbits 
-optc-I../libraries/base/include -H16m -O -I. -Iinclude -Rghc-timing  
-ignore-package Cabal -I../libraries -fglasgow-exts -no-recomp    -c 
cbits/unicode.c -o cbits/unicode.o
cbits/unicode.c:1:63: error: floating constant in preprocessor 
expression
<<ghc: 13597044 bytes, 3 GCs, 103440/103440 avg/max bytes residency (1 
samples), 15M in use, 0.00 INIT (0.00 elapsed), 0.01 MUT (0.17 
elapsed), 0.01 GC (0.02 elapsed) :ghc>>
make[2]: *** [cbits/unicode.o] Error 1
make[1]: *** [boot] Error 2
make: *** [stage1] Error 1