diff --git a/src/configure b/src/configure
index a0ebf8bdad..5f78312c24 100755
--- a/src/configure
+++ b/src/configure
@@ -1341,7 +1341,7 @@ Optional Features:
   --enable-shared         create shared libraries
   --enable-dynlib         same as --enable-shared
   --enable-lt=<prog>      use <prog> instead of libtool; disable to use bundled
-  --enable-libffi         use installed libffi (enabled by default)
+  --enable-libffi         use installed libffi (enabled by default for Unix)
   --enable-sdk=<path>     use Mac OS X 10.4 SDK directory
   --enable-xonx           use Unix style (e.g., use Gtk) for Mac OS X
   --enable-libfw          install Mac OS X frameworks to /Library/Frameworks
@@ -2043,7 +2043,7 @@ fi
 if test "${enable_libffi+set}" = set; then
   enableval=$enable_libffi;
 else
-  enable_libffi=yes
+  enable_libffi=default
 fi
 
 
@@ -2322,6 +2322,7 @@ show_explicitly_enabled "${enable_orig}" "Original install tree"
 show_explicitly_disabled "${enable_jit}" JIT
 
 show_explicitly_disabled "${enable_foreign}" Foreign
+show_explicitly_enabled "${enable_libffi}" "Installed libffi"
 show_explicitly_disabled "${enable_libffi}" "Installed libffi"
 
 show_explicitly_enabled "${enable_places}" Places
@@ -5363,6 +5364,17 @@ _ACEOF
   fi
 fi
 
+if test "${enable_libffi}" = "default" ; then
+  case "$host_os" in
+  darwin*)
+        enable_libffi=no
+  ;;
+  *)
+        enable_libffi=yes
+  ;;
+  esac
+fi
+
 if test "${enable_libffi}" = "yes" ; then
  if test "${enable_foreign}" = "yes" ; then
   { echo "$as_me:$LINENO: checking for libffi" >&5
diff --git a/src/racket/configure.ac b/src/racket/configure.ac
index e39b4614e1..397f2c2089 100644
--- a/src/racket/configure.ac
+++ b/src/racket/configure.ac
@@ -44,7 +44,7 @@ AC_ARG_ENABLE(shared,  [  --enable-shared         create shared libraries])
 AC_ARG_ENABLE(dynlib,  [  --enable-dynlib         same as --enable-shared])
 AC_ARG_ENABLE(lt,      [  --enable-lt=<prog>      use <prog> instead of libtool; disable to use bundled], LIBTOOLPROG="$enableval", enable_lt=default)
 
-AC_ARG_ENABLE(libffi,  [  --enable-libffi         use installed libffi (enabled by default)], , enable_libffi=yes)
+AC_ARG_ENABLE(libffi,  [  --enable-libffi         use installed libffi (enabled by default for Unix)], , enable_libffi=default)
 
 AC_ARG_ENABLE(sdk,     [  --enable-sdk=<path>     use Mac OS X 10.4 SDK directory])
 AC_ARG_ENABLE(xonx,    [  --enable-xonx           use Unix style (e.g., use Gtk) for Mac OS X])
@@ -255,6 +255,7 @@ show_explicitly_enabled "${enable_orig}" "Original install tree"
 show_explicitly_disabled "${enable_jit}" JIT
 
 show_explicitly_disabled "${enable_foreign}" Foreign
+show_explicitly_enabled "${enable_libffi}" "Installed libffi"
 show_explicitly_disabled "${enable_libffi}" "Installed libffi"
 
 show_explicitly_enabled "${enable_places}" Places
@@ -860,6 +861,17 @@ if test "${try_kqueue_syscall}" = "yes" ; then
   fi
 fi
 
+if test "${enable_libffi}" = "default" ; then
+  case "$host_os" in
+  darwin*)
+        enable_libffi=no
+  ;;
+  *)
+        enable_libffi=yes
+  ;;
+  esac
+fi
+
 if test "${enable_libffi}" = "yes" ; then
  if test "${enable_foreign}" = "yes" ; then
   AC_MSG_CHECKING([for libffi])