--- a/browser/config/mozconfigs/linux64/debug-asan
+++ b/browser/config/mozconfigs/linux64/debug-asan
@@ -1,13 +1,15 @@
 # Use at least -O1 for optimization to avoid stack space
 # exhaustions caused by Clang function inlining.
 ac_add_options --enable-debug
 ac_add_options --enable-optimize="-O1"
 
+. $topsrcdir/build/mozconfig.stylo
+
 # ASan specific options on Linux
 ac_add_options --enable-valgrind
 
 . $topsrcdir/build/unix/mozconfig.asan
 
 export PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig:/usr/share/pkgconfig
 . $topsrcdir/build/unix/mozconfig.gtk
 

--- a/browser/config/mozconfigs/linux64/hazards
+++ b/browser/config/mozconfigs/linux64/hazards
@@ -15,16 +15,18 @@ MOZ_AUTOMATION_PACKAGE=0
 MOZ_AUTOMATION_PACKAGE_TESTS=0
 MOZ_AUTOMATION_UPLOAD=0
 
 . "$topsrcdir/build/mozconfig.common"
 ac_add_options --enable-elf-hack
 
 . "$topsrcdir/build/unix/mozconfig.stdcxx"
 
+. "$topsrcdir/build/mozconfig.stylo"
+
 # The objdir must be at a known location so its path can be stripped from the
 # filenames stored by the analysis
 mk_add_options MOZ_OBJDIR=obj-analyzed
 
 # The configuration options are chosen to compile the most code
 # (--enable-debug, --enable-tests) in the trickiest way possible
 # (--enable-optimize) to maximize the chance of seeing tricky static orderings.
 ac_add_options --enable-debug

--- a/build/mozconfig.stylo
+++ b/build/mozconfig.stylo
@@ -1,6 +1,2 @@
 # Tell the build system where to find llvm-config for builds on automation.
 export LLVM_CONFIG="${TOOLTOOL_DIR:-$topsrcdir}/clang/bin/llvm-config"
-
-# TODO remove once configure defaults to stylo once stylo enabled
-# on all platforms.
-ac_add_options --enable-stylo=build

--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -588,27 +588,37 @@ simple_keyfile('Adjust SDK')
 
 id_and_secret_keyfile('Leanplum SDK')
 
 # Servo integration
 # ==============================================================
 option('--enable-stylo', nargs='?', choices=('build',),
        help='Include Stylo in the build and/or enable it at runtime')
 
-@depends('--enable-stylo', '--help')
-def stylo_config(value, _):
+@depends('--enable-stylo', '--help', target)
+def stylo_config(value, _, target):
     build_stylo = None
     enable_stylo = None
 
-    # The default is to not build Stylo at all.
+    # If nothing is specified, default to building stylo where possible.
     if value.origin == 'default':
-        pass
+        if target.os == 'GNU' and target.bitness == 32:
+            # The clang setup we use in automation is a little unusual, and
+            # doesn't play well with bindgen on 32-bit Linux.
+            pass
+        elif target.os == 'Android':
+            # Stylo on Android is happening Later(tm).
+            pass
+        else:
+            build_stylo = True
     elif len(value) and value[0] == 'build':
+        # Build but disable by request.
         build_stylo = True
     elif bool(value):
+        # Build and enable.
         build_stylo = True
         enable_stylo = True
 
     return namespace(
         build = build_stylo,
         enable = enable_stylo,
     )