Building ghc-6.4-branch on Solaris

Hi,

after faking my way around the not-enough-register in libraries/OpenGL
recently reported on the HOpenGL list, I ran into the following:

------------------------------------------------------------------------
==fptools== gmake all - --no-print-directory -r;
 in /nfs/myrtle/d24/part2/home/cur/as49/source/ghc-6.4-
branch/hslibs/posix/cbits
------------------------------------------------------------------------
gcc -O -Wall -I../../../ghc/includes -I../../../ghc/rts 
-I/core/include    -c env.c -o env.p_o
cc1: /core/include: Not a directory

The directory /core/include doesn't exist, what the makefile says is

./hslibs/posix/cbits/Makefile:          -I$(GHC_LIB_DIR)/core/include

however, I can't find GHC_LIB_DIR in any of the config files. Is it
dead?

Any help appreciated,
Axel.