--- a/b2g/confvars.sh
+++ b/b2g/confvars.sh
@@ -14,17 +14,16 @@ MOZ_B2G_VERSION=2.6.0.0-prerelease
 MOZ_B2G_OS_NAME=Boot2Gecko
 
 MOZ_BRANDING_DIRECTORY=b2g/branding/unofficial
 MOZ_OFFICIAL_BRANDING_DIRECTORY=b2g/branding/official
 # MOZ_APP_DISPLAYNAME is set by branding/configure.sh
 
 MOZ_SAFE_BROWSING=1
 
-MOZ_WEBSMS_BACKEND=1
 MOZ_NO_SMART_CARDS=1
 MOZ_APP_STATIC_INI=1
 NSS_DISABLE_DBM=1
 MOZ_NO_EV_CERTS=1
 
 MOZ_WEBSPEECH=1
 if test -n "$NIGHTLY_BUILD"; then
 MOZ_WEBSPEECH_MODELS=1

--- a/b2g/graphene/confvars.sh
+++ b/b2g/graphene/confvars.sh
@@ -22,17 +22,16 @@ MOZ_B2G_OS_NAME=Boot2Gecko
 
 MOZ_BRANDING_DIRECTORY=b2g/branding/unofficial
 MOZ_OFFICIAL_BRANDING_DIRECTORY=b2g/branding/official
 # MOZ_APP_DISPLAYNAME is set by branding/configure.sh
 
 MOZ_SAFE_BROWSING=1
 MOZ_CAPTIVEDETECT=1
 
-MOZ_WEBSMS_BACKEND=1
 MOZ_NO_SMART_CARDS=1
 MOZ_APP_STATIC_INI=1
 NSS_NO_LIBPKIX=1
 NSS_DISABLE_DBM=1
 
 if test "$OS_TARGET" = "Android"; then
 MOZ_CAPTURE=1
 MOZ_RAW=1

--- a/build/moz.configure/old.configure
+++ b/build/moz.configure/old.configure
@@ -244,17 +244,16 @@ def old_configure_options(*options):
     '--enable-tree-freetype',
     '--enable-ui-locale',
     '--enable-universalchardet',
     '--enable-updater',
     '--enable-url-classifier',
     '--enable-valgrind',
     '--enable-verify-mar',
     '--enable-webrtc',
-    '--enable-websms-backend',
     '--enable-webspeech',
     '--enable-webspeechtestbackend',
     '--enable-xul',
     '--enable-zipwriter',
     '--no-create',
     '--prefix',
     '--with-android-cxx-stl',
     '--with-android-distribution-directory',

--- a/old-configure.in
+++ b/old-configure.in
@@ -2360,17 +2360,16 @@ MOZ_NO_SMART_CARDS=
 NSS_DISABLE_DBM=
 NECKO_COOKIES=1
 NECKO_PROTOCOLS_DEFAULT="about data file ftp http res viewsource websocket wyciwyg device"
 if test -n "$MOZ_RTSP"; then
   NECKO_PROTOCOLS_DEFAULT="$NECKO_PROTOCOLS_DEFAULT rtsp"
 fi
 BUILD_CTYPES=1
 MOZ_USE_NATIVE_POPUP_WINDOWS=
-MOZ_WEBSMS_BACKEND=
 MOZ_EXCLUDE_HYPHENATION_DICTIONARIES=
 MOZ_INSTALL_TRACKING=
 ACCESSIBILITY=1
 MOZ_TIME_MANAGER=
 MOZ_SIMPLEPUSH=
 MOZ_PAY=
 MOZ_AUDIO_CHANNEL_MANAGER=
 MOZ_CONTENT_SANDBOX=
@@ -2859,29 +2858,16 @@ then
     then
         PKG_CHECK_MODULES(MOZ_DBUS, dbus-1 >= $DBUS_VERSION)
         PKG_CHECK_MODULES(MOZ_DBUS_GLIB, dbus-glib-1 >= $DBUS_VERSION)
         AC_DEFINE(MOZ_ENABLE_DBUS)
     fi
 fi
 AC_SUBST(MOZ_ENABLE_DBUS)
 
-dnl ========================================================
-dnl = Disable WebSMS backend
-dnl ========================================================
-MOZ_ARG_DISABLE_BOOL(websms-backend,
-[  --disable-websms-backend
-                           Disable WebSMS backend],
-    MOZ_WEBSMS_BACKEND=,
-    MOZ_WEBSMS_BACKEND=1)
-
-if test -n "$MOZ_WEBSMS_BACKEND"; then
-    AC_DEFINE(MOZ_WEBSMS_BACKEND)
-fi
-
 dnl =========================================================
 dnl = Whether to exclude hyphenations files in the build
 dnl =========================================================
 if test -n "$MOZ_EXCLUDE_HYPHENATION_DICTIONARIES"; then
     AC_DEFINE(MOZ_EXCLUDE_HYPHENATION_DICTIONARIES)
 fi
 
 dnl ========================================================
@@ -5770,17 +5756,16 @@ AC_SUBST(MOZ_ANGLE_RENDERER)
 AC_SUBST(MOZ_D3D_CPU_SUFFIX)
 AC_SUBST(MOZ_HAS_WINSDK_WITH_D3D)
 AC_SUBST(MOZ_D3DCOMPILER_VISTA_DLL)
 AC_SUBST(MOZ_D3DCOMPILER_VISTA_DLL_PATH)
 AC_SUBST(MOZ_DIRECTX_SDK_PATH)
 AC_SUBST(MOZ_D3DCOMPILER_XP_DLL)
 AC_SUBST(MOZ_D3DCOMPILER_XP_CAB)
 
-AC_SUBST(MOZ_WEBSMS_BACKEND)
 AC_SUBST(MOZ_ANDROID_APPLICATION_CLASS)
 AC_SUBST(MOZ_ANDROID_BROWSER_INTENT_CLASS)
 AC_SUBST(MOZ_ANDROID_SEARCH_INTENT_CLASS)
 AC_SUBST(MOZ_EXCLUDE_HYPHENATION_DICTIONARIES)
 AC_SUBST(MOZ_INSTALL_TRACKING)
 AC_SUBST(ENABLE_STRIP)
 AC_SUBST(PKG_SKIP_STRIP)
 AC_SUBST(STRIP_FLAGS)

--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -535,8 +535,24 @@ def no_speechd_on_non_gtk(toolkit):
 
 imply_option('--enable-synth-speechd', no_speechd_on_non_gtk,
              reason='--enable-default-toolkit')
 
 option('--disable-synth-speechd', help='Disable speech-dispatcher support')
 
 set_config('MOZ_SYNTH_SPEECHD',
            depends_if('--disable-synth-speechd')(lambda _: True))
+
+# WebSMS
+# ==============================================================
+@depends(build_project, '--help')
+def websms_default(build_project, _):
+    return build_project in ('b2g', 'b2g/graphene')
+
+option('--enable-websms-backend', default=websms_default,
+       help='Enable WebSMS backend')
+
+@depends_if('--enable-websms-backend')
+def websms_backend(value):
+    return True
+
+set_config('MOZ_WEBSMS_BACKEND', websms_backend)
+set_define('MOZ_WEBSMS_BACKEND', websms_backend)