ghc passing -undef to preprocessor and thereby eliminating OS specific defines

Hey, I am trying to adapt some code in the libraries when compiling for android (i.E. because some things are different on android to other posix systems). So in C code I would just do "#ifdef __ANDROID__". While in the *.h and *.c files it seems to work, it does not work in *.hs files. I noted that the preprocessor is run like this: arm-linux-androideabi-gcc -E -undef -traditional -fno-stack-protector -DTABLES_NEXT_TO_CODE The "-undef" parameter is causing the __ANDROID__ define to be removed. Does it make sense to pass "-undef" to the preprocessor? Any other Ideas how I could adapt the code for android? Thanks! Nathan