I'm trying to get mod_auth_kerb installed, but I can't seem to find any information on compiling it on OS X. I'm getting the following when I attempt to compile:

./apxs.sh "-I. -Ispnegokrb5 -I/include  " "-dynamic -g -O2 -arch x86_64 -Wl,-search_paths_first -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lresolv  -lresolv" "" "/Applications/XAMPP/xamppfiles/bin/apxs" "-c" "src/mod_auth_kerb.c"
/Applications/XAMPP/xamppfiles/build/libtool --silent --mode=compile gcc -prefer-pic -I/Applications/XAMPP/xamppfiles/include -L/Applications/XAMPP/xamppfiles/lib -mmacosx-version-min=10.4 -arch i386 -arch ppc  -DDARWIN -DSIGPROCMASK_SETS_THREAD_MASK -no-cpp-precomp  -I/Applications/XAMPP/xamppfiles/include  -I/Applications/XAMPP/xamppfiles/include   -I/Applications/XAMPP/xamppfiles/include -I/Applications/XAMPP/xamppfiles/include -I. -Ispnegokrb5 -I/include  -c -o src/mod_auth_kerb.lo src/mod_auth_kerb.c && touch src/mod_auth_kerb.slo
src/mod_auth_kerb.c: In function ‘authenticate_user_krb5pwd’:
src/mod_auth_kerb.c:1030: warning: passing argument 8 of ‘verify_krb5_user’ discards qualifiers from pointer target type
src/mod_auth_kerb.c: In function ‘authenticate_user_krb5pwd’:
src/mod_auth_kerb.c:1030: warning: passing argument 8 of ‘verify_krb5_user’ discards qualifiers from pointer target type
/Applications/XAMPP/xamppfiles/build/libtool --silent --mode=link gcc -o src/mod_auth_kerb.la -dynamic -g -O2 -arch x86_64 -Wl,-search_paths_first -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lresolv -lresolv  -rpath /Applications/XAMPP/xamppfiles/modules -module -avoid-version    src/mod_auth_kerb.lo
ld: warning: in src/.libs/mod_auth_kerb.o, missing required architecture x86_64 in file
warning: no debug symbols in executable (-arch x86_64)

I'm configuring as follows:

./configure --with-krb4=no CFLAGS='-g -O2 -arch x86_64'

I should mention that I'm using XAMPP with the development package on this machine.