diff --git a/BasiliskII/src/Unix/configure b/BasiliskII/src/Unix/configure
index 91b99865..690f570b 100755
--- a/BasiliskII/src/Unix/configure
+++ b/BasiliskII/src/Unix/configure
@@ -773,12 +773,92 @@ else
   fi
 fi
 
+echo $ac_n "checking how to run the C preprocessor""... $ac_c" 1>&6
+echo "configure:778: checking how to run the C preprocessor" >&5
+# On Suns, sometimes $CPP names a directory.
+if test -n "$CPP" && test -d "$CPP"; then
+  CPP=
+fi
+if test -z "$CPP"; then
+if eval "test \"`echo '$''{'ac_cv_prog_CPP'+set}'`\" = set"; then
+  echo $ac_n "(cached) $ac_c" 1>&6
+else
+    # This must be in double quotes, not single quotes, because CPP may get
+  # substituted into the Makefile and "${CC-cc}" will confuse make.
+  CPP="${CC-cc} -E"
+  # On the NeXT, cc -E runs the code through the compiler's parser,
+  # not just through cpp.
+  cat > conftest.$ac_ext <<EOF
+#line 793 "configure"
+#include "confdefs.h"
+#include <assert.h>
+Syntax Error
+EOF
+ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
+{ (eval echo configure:799: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
+if test -z "$ac_err"; then
+  :
+else
+  echo "$ac_err" >&5
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  CPP="${CC-cc} -E -traditional-cpp"
+  cat > conftest.$ac_ext <<EOF
+#line 810 "configure"
+#include "confdefs.h"
+#include <assert.h>
+Syntax Error
+EOF
+ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
+{ (eval echo configure:816: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
+if test -z "$ac_err"; then
+  :
+else
+  echo "$ac_err" >&5
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  CPP="${CC-cc} -nologo -E"
+  cat > conftest.$ac_ext <<EOF
+#line 827 "configure"
+#include "confdefs.h"
+#include <assert.h>
+Syntax Error
+EOF
+ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
+{ (eval echo configure:833: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
+ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
+if test -z "$ac_err"; then
+  :
+else
+  echo "$ac_err" >&5
+  echo "configure: failed program was:" >&5
+  cat conftest.$ac_ext >&5
+  rm -rf conftest*
+  CPP=/lib/cpp
+fi
+rm -f conftest*
+fi
+rm -f conftest*
+fi
+rm -f conftest*
+  ac_cv_prog_CPP="$CPP"
+fi
+  CPP="$ac_cv_prog_CPP"
+else
+  ac_cv_prog_CPP="$CPP"
+fi
+echo "$ac_t""$CPP" 1>&6
+
 for ac_prog in $CCC c++ g++ gcc CC cxx cc++ cl
 do
 # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
 echo $ac_n "checking for $ac_word""... $ac_c" 1>&6
-echo "configure:782: checking for $ac_word" >&5
+echo "configure:862: checking for $ac_word" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_CXX'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -810,7 +890,7 @@ test -n "$CXX" || CXX="gcc"
 
 
 echo $ac_n "checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) works""... $ac_c" 1>&6
-echo "configure:814: checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) works" >&5
+echo "configure:894: checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) works" >&5
 
 ac_ext=C
 # CXXFLAGS is not in ac_cpp because -g, -O, etc. are not valid cpp options.
@@ -821,12 +901,12 @@ cross_compiling=$ac_cv_prog_cxx_cross
 
 cat > conftest.$ac_ext << EOF
 
-#line 825 "configure"
+#line 905 "configure"
 #include "confdefs.h"
 
 int main(){return(0);}
 EOF
-if { (eval echo configure:830: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:910: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   ac_cv_prog_cxx_works=yes
   # If we can't run a trivial program, we are probably using a cross compiler.
   if (./conftest; exit) 2>/dev/null; then
@@ -852,12 +932,12 @@ if test $ac_cv_prog_cxx_works = no; then
   { echo "configure: error: installation or configuration problem: C++ compiler cannot create executables." 1>&2; exit 1; }
 fi
 echo $ac_n "checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) is a cross-compiler""... $ac_c" 1>&6
-echo "configure:856: checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) is a cross-compiler" >&5
+echo "configure:936: checking whether the C++ compiler ($CXX $CXXFLAGS $LDFLAGS) is a cross-compiler" >&5
 echo "$ac_t""$ac_cv_prog_cxx_cross" 1>&6
 cross_compiling=$ac_cv_prog_cxx_cross
 
 echo $ac_n "checking whether we are using GNU C++""... $ac_c" 1>&6
-echo "configure:861: checking whether we are using GNU C++" >&5
+echo "configure:941: checking whether we are using GNU C++" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_gxx'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -866,7 +946,7 @@ else
   yes;
 #endif
 EOF
-if { ac_try='${CXX-g++} -E conftest.C'; { (eval echo configure:870: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; } | egrep yes >/dev/null 2>&1; then
+if { ac_try='${CXX-g++} -E conftest.C'; { (eval echo configure:950: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }; } | egrep yes >/dev/null 2>&1; then
   ac_cv_prog_gxx=yes
 else
   ac_cv_prog_gxx=no
@@ -885,7 +965,7 @@ ac_test_CXXFLAGS="${CXXFLAGS+set}"
 ac_save_CXXFLAGS="$CXXFLAGS"
 CXXFLAGS=
 echo $ac_n "checking whether ${CXX-g++} accepts -g""... $ac_c" 1>&6
-echo "configure:889: checking whether ${CXX-g++} accepts -g" >&5
+echo "configure:969: checking whether ${CXX-g++} accepts -g" >&5
 if eval "test \"`echo '$''{'ac_cv_prog_cxx_g'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -917,7 +997,7 @@ else
 fi
 
 echo $ac_n "checking whether ${MAKE-make} sets \${MAKE}""... $ac_c" 1>&6
-echo "configure:921: checking whether ${MAKE-make} sets \${MAKE}" >&5
+echo "configure:1001: checking whether ${MAKE-make} sets \${MAKE}" >&5
 set dummy ${MAKE-make}; ac_make=`echo "$2" | sed 'y%./+-%__p_%'`
 if eval "test \"`echo '$''{'ac_cv_prog_make_${ac_make}_set'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
@@ -974,7 +1054,7 @@ ac_configure=$ac_aux_dir/configure # This should be Cygnus configure.
 # SVR4 /usr/ucb/install, which tries to use the nonexistent group "staff"
 # ./install, which can be erroneously created by make from ./install.sh.
 echo $ac_n "checking for a BSD compatible install""... $ac_c" 1>&6
-echo "configure:978: checking for a BSD compatible install" >&5
+echo "configure:1058: checking for a BSD compatible install" >&5
 if test -z "$INSTALL"; then
 if eval "test \"`echo '$''{'ac_cv_path_install'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
@@ -1027,86 +1107,6 @@ test -z "$INSTALL_SCRIPT" && INSTALL_SCRIPT='${INSTALL_PROGRAM}'
 test -z "$INSTALL_DATA" && INSTALL_DATA='${INSTALL} -m 644'
 
 
-echo $ac_n "checking how to run the C preprocessor""... $ac_c" 1>&6
-echo "configure:1032: checking how to run the C preprocessor" >&5
-# On Suns, sometimes $CPP names a directory.
-if test -n "$CPP" && test -d "$CPP"; then
-  CPP=
-fi
-if test -z "$CPP"; then
-if eval "test \"`echo '$''{'ac_cv_prog_CPP'+set}'`\" = set"; then
-  echo $ac_n "(cached) $ac_c" 1>&6
-else
-    # This must be in double quotes, not single quotes, because CPP may get
-  # substituted into the Makefile and "${CC-cc}" will confuse make.
-  CPP="${CC-cc} -E"
-  # On the NeXT, cc -E runs the code through the compiler's parser,
-  # not just through cpp.
-  cat > conftest.$ac_ext <<EOF
-#line 1047 "configure"
-#include "confdefs.h"
-#include <assert.h>
-Syntax Error
-EOF
-ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1053: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
-ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
-if test -z "$ac_err"; then
-  :
-else
-  echo "$ac_err" >&5
-  echo "configure: failed program was:" >&5
-  cat conftest.$ac_ext >&5
-  rm -rf conftest*
-  CPP="${CC-cc} -E -traditional-cpp"
-  cat > conftest.$ac_ext <<EOF
-#line 1064 "configure"
-#include "confdefs.h"
-#include <assert.h>
-Syntax Error
-EOF
-ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1070: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
-ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
-if test -z "$ac_err"; then
-  :
-else
-  echo "$ac_err" >&5
-  echo "configure: failed program was:" >&5
-  cat conftest.$ac_ext >&5
-  rm -rf conftest*
-  CPP="${CC-cc} -nologo -E"
-  cat > conftest.$ac_ext <<EOF
-#line 1081 "configure"
-#include "confdefs.h"
-#include <assert.h>
-Syntax Error
-EOF
-ac_try="$ac_cpp conftest.$ac_ext >/dev/null 2>conftest.out"
-{ (eval echo configure:1087: \"$ac_try\") 1>&5; (eval $ac_try) 2>&5; }
-ac_err=`grep -v '^ *+' conftest.out | grep -v "^conftest.${ac_ext}\$"`
-if test -z "$ac_err"; then
-  :
-else
-  echo "$ac_err" >&5
-  echo "configure: failed program was:" >&5
-  cat conftest.$ac_ext >&5
-  rm -rf conftest*
-  CPP=/lib/cpp
-fi
-rm -f conftest*
-fi
-rm -f conftest*
-fi
-rm -f conftest*
-  ac_cv_prog_CPP="$CPP"
-fi
-  CPP="$ac_cv_prog_CPP"
-else
-  ac_cv_prog_CPP="$CPP"
-fi
-echo "$ac_t""$CPP" 1>&6
-
 # If we find X, set shell vars x_includes and x_libraries to the
 # paths, otherwise set no_x=yes.
 # Uses ac_ vars as temps to allow command line to override cache and checks.
@@ -3769,12 +3769,12 @@ s%@oldincludedir@%$oldincludedir%g
 s%@infodir@%$infodir%g
 s%@mandir@%$mandir%g
 s%@CC@%$CC%g
+s%@CPP@%$CPP%g
 s%@CXX@%$CXX%g
 s%@SET_MAKE@%$SET_MAKE%g
 s%@INSTALL_PROGRAM@%$INSTALL_PROGRAM%g
 s%@INSTALL_SCRIPT@%$INSTALL_SCRIPT%g
 s%@INSTALL_DATA@%$INSTALL_DATA%g
-s%@CPP@%$CPP%g
 s%@X_CFLAGS@%$X_CFLAGS%g
 s%@X_PRE_LIBS@%$X_PRE_LIBS%g
 s%@X_LIBS@%$X_LIBS%g
diff --git a/BasiliskII/src/Unix/configure.in b/BasiliskII/src/Unix/configure.in
index 2ba90a8c..19d0a9cb 100644
--- a/BasiliskII/src/Unix/configure.in
+++ b/BasiliskII/src/Unix/configure.in
@@ -13,6 +13,7 @@ AC_ARG_ENABLE(ui,  [  --enable-ui             use GTK user interface (default)],
 
 dnl Checks for programs.
 AC_PROG_CC
+AC_PROG_CPP
 AC_PROG_CXX
 AC_PROG_MAKE_SET
 AC_PROG_INSTALL