--- a/build/moz.configure/old.configure
+++ b/build/moz.configure/old.configure
@@ -164,17 +164,16 @@ def old_configure_options(*options):
     '--enable-b2g-camera',
     '--enable-b2g-ril',
     '--enable-bundled-fonts',
     '--enable-clang-plugin',
     '--enable-content-sandbox',
     '--enable-cookies',
     '--enable-cpp-rtti',
     '--enable-crashreporter',
-    '--enable-ctypes',
     '--enable-dbus',
     '--enable-debug-js-modules',
     '--enable-directshow',
     '--enable-dtrace',
     '--enable-dump-painting',
     '--enable-elf-hack',
     '--enable-extensions',
     '--enable-faststripe',

--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -2097,32 +2097,23 @@ AC_SUBST_LIST(EDITLINE_LIBS)
 
 dnl ========================================================
 dnl =
 dnl = Standalone module options
 dnl =
 dnl ========================================================
 MOZ_ARG_HEADER(Standalone module options (Not for building Mozilla))
 
-dnl ========================================================
-dnl = Build jsctypes if it's enabled
-dnl ========================================================
-MOZ_ARG_ENABLE_BOOL(ctypes,
-[  --enable-ctypes         Enable js-ctypes (default=no)],
-    BUILD_CTYPES=1,
-    BUILD_CTYPES= )
-JS_HAS_CTYPES=$BUILD_CTYPES
-AC_SUBST(JS_HAS_CTYPES)
-AC_SUBST(BUILD_CTYPES)
 if test "$JS_HAS_CTYPES"; then
+  dnl JS_HAS_CTYPES is defined by Python configure. This check remains
+  dnl as long as determining $AS remains in old-configure.
   dnl Error out if we're on MSVC and MASM is unavailable.
   if test -n "$_MSC_VER" -a \( "$AS" != "ml.exe" -a "$AS" != "ml64.exe" \); then
     AC_MSG_ERROR([\"$AS\" is not a suitable assembler to build js-ctypes. If you are building with MS Visual Studio 8 Express, you may download the MASM 8.0 package, upgrade to Visual Studio 9 Express, or install the Vista SDK. Or do not use --enable-ctypes.])
   fi
-  AC_DEFINE(JS_HAS_CTYPES)
 fi
 
 dnl ========================================================
 dnl =
 dnl = Options for generating the shell as a script
 dnl =
 dnl ========================================================
 

--- a/moz.configure
+++ b/moz.configure
@@ -97,16 +97,40 @@ include_when('build/moz.configure/toolch
              when='--enable-compile-environment')
 include_when('build/moz.configure/memory.configure',
              when='--enable-compile-environment')
 include_when('build/moz.configure/headers.configure',
              when='--enable-compile-environment')
 include_when('build/moz.configure/warnings.configure',
              when='--enable-compile-environment')
 
+
+@depends(building_js, '--help')
+def ctypes_default(building_js, _):
+    return not building_js
+
+js_option('--enable-ctypes', help='Enable js-ctypes',
+          default=ctypes_default)
+
+build_ctypes = depends_if('--enable-ctypes')(lambda _: True)
+
+set_config('BUILD_CTYPES', build_ctypes)
+set_define('BUILD_CTYPES', build_ctypes)
+add_old_configure_assignment('BUILD_CTYPES', build_ctypes)
+
+@depends(build_ctypes, building_js)
+def js_has_ctypes(ctypes, js):
+    if ctypes and js:
+        return True
+
+set_config('JS_HAS_CTYPES', js_has_ctypes)
+set_define('JS_HAS_CTYPES', js_has_ctypes)
+add_old_configure_assignment('JS_HAS_CTYPES', js_has_ctypes)
+
+
 @dependable
 @imports(_from='mozbuild.backend', _import='backends')
 def build_backends_choices():
     return tuple(backends)
 
 
 @deprecated_option('--enable-build-backend', nargs='+',
                    choices=build_backends_choices)

--- a/old-configure.in
+++ b/old-configure.in
@@ -2362,17 +2362,16 @@ MOZ_TOOLKIT_SEARCH=1
 MOZ_UI_LOCALE=en-US
 MOZ_UNIVERSALCHARDET=1
 MOZ_URL_CLASSIFIER=
 MOZ_XUL=1
 MOZ_ZIPWRITER=1
 MOZ_NO_SMART_CARDS=
 NECKO_COOKIES=1
 NECKO_PROTOCOLS_DEFAULT="about data file ftp http res viewsource websocket wyciwyg device"
-BUILD_CTYPES=1
 MOZ_USE_NATIVE_POPUP_WINDOWS=
 MOZ_EXCLUDE_HYPHENATION_DICTIONARIES=
 MOZ_INSTALL_TRACKING=
 ACCESSIBILITY=1
 MOZ_TIME_MANAGER=
 MOZ_SIMPLEPUSH=
 MOZ_AUDIO_CHANNEL_MANAGER=
 MOZ_CONTENT_SANDBOX=
@@ -5573,28 +5572,16 @@ dnl
 if test "$OS_TARGET" != Android -a x"$MOZ_WIDGET_TOOLKIT" != x"gonk"; then
     AC_DEFINE(ENABLE_MARIONETTE)
 fi
 AC_SUBST(ENABLE_MARIONETTE)
 if test "$ENABLE_MARIONETTE"; then
     AC_DEFINE(ENABLE_MARIONETTE)
 fi
 
-dnl
-dnl Build jsctypes on the platforms we can, unless it's explicitly disabled.
-dnl
-MOZ_ARG_DISABLE_BOOL(ctypes,
-[  --disable-ctypes        Disable js-ctypes],
-    BUILD_CTYPES=,
-    BUILD_CTYPES=1)
-AC_SUBST(BUILD_CTYPES)
-if test "$BUILD_CTYPES"; then
-    AC_DEFINE(BUILD_CTYPES)
-fi
-
 dnl ========================================================
 if test "$MOZ_DEBUG" -o "$MOZ_DMD"; then
     MOZ_COMPONENTS_VERSION_SCRIPT_LDFLAGS=
 fi
 
 dnl ========================================================
 dnl =
 dnl = Maintainer debug option (no --enable equivalent)
@@ -6261,20 +6248,16 @@ ac_configure_args="$_SUBDIR_CONFIG_ARGS"
 # --with-system-nspr will have been converted into the relevant $NSPR_CFLAGS
 # and $NSPR_LIBS.
 ac_configure_args="`echo $ac_configure_args | sed -e 's/--with-system-nspr\S* *//'`"
 
 if test "$_INTL_API" = no; then
     ac_configure_args="$ac_configure_args --without-intl-api"
 fi
 
-if test "$BUILD_CTYPES"; then
-    # Build js-ctypes on the platforms we can.
-    ac_configure_args="$ac_configure_args --enable-ctypes"
-fi
 if test -n "$NSPR_CFLAGS" -o -n "$NSPR_LIBS"; then
     ac_configure_args="$ac_configure_args --with-nspr-cflags='$NSPR_CFLAGS'"
     ac_configure_args="$ac_configure_args --with-nspr-libs='$NSPR_LIBS'"
 fi
 ac_configure_args="$ac_configure_args --prefix=$dist"
 if test -n "$ZLIB_IN_MOZGLUE"; then
    MOZ_ZLIB_LIBS=
 fi