--- a/build/autoconf/android.m4
+++ b/build/autoconf/android.m4
@@ -6,69 +6,19 @@ AC_DEFUN([MOZ_ANDROID_NDK],
 [
 
 MOZ_ARG_WITH_STRING(android-cxx-stl,
 [  --with-android-cxx-stl=VALUE
                           use the specified C++ STL (stlport, libstdc++, libc++)],
     android_cxx_stl=$withval,
     android_cxx_stl=libc++)
 
-define([MIN_ANDROID_VERSION], [9])
-android_version=MIN_ANDROID_VERSION
-
-MOZ_ARG_WITH_STRING(android-version,
-[  --with-android-version=VER
-                          android platform version, default] MIN_ANDROID_VERSION,
-    android_version=$withval)
-
-if test $android_version -lt MIN_ANDROID_VERSION ; then
-    AC_MSG_ERROR([--with-android-version must be at least MIN_ANDROID_VERSION.])
-fi
-
 case "$target" in
 *-android*|*-linuxandroid*)
-    AC_MSG_CHECKING([for android platform directory])
-
-    case "$target_cpu" in
-    arm)
-        target_name=arm
-        ;;
-    i?86)
-        target_name=x86
-        ;;
-    mipsel)
-        target_name=mips
-        ;;
-    esac
-
-    dnl Not all Android releases have their own platform release. We use
-    dnl the next lower platform version in these cases.
-    case $android_version in
-    11|10)
-        android_platform_version=9
-        ;;
-    20)
-        android_platform_version=19
-        ;;
-    22)
-        android_platform_version=21
-        ;;
-    *)
-        android_platform_version=$android_version
-        ;;
-    esac
-
-    android_platform="$android_ndk"/platforms/android-"$android_platform_version"/arch-"$target_name"
-
-    if test -d "$android_platform" ; then
-        AC_MSG_RESULT([$android_platform])
-    else
-        AC_MSG_ERROR([not found. Please check your NDK. With the current configuration, it should be in $android_platform])
-    fi
-
+    dnl $android_platform will be set for us by Python configure.
     CPPFLAGS="-idirafter $android_platform/usr/include $CPPFLAGS"
     CFLAGS="-fno-short-enums -fno-exceptions $CFLAGS"
     CXXFLAGS="-fno-short-enums -fno-exceptions $CXXFLAGS"
     ASFLAGS="-idirafter $android_platform/usr/include -DANDROID $ASFLAGS"
 
     dnl Add --allow-shlib-undefined, because libGLESv2 links to an
     dnl undefined symbol (present on the hardware, just not in the
     dnl NDK.)

--- a/build/moz.configure/android-ndk.configure
+++ b/build/moz.configure/android-ndk.configure
@@ -9,27 +9,87 @@ js_option('--with-android-ndk', nargs=1,
           help='location where the Android NDK can be found')
 
 js_option('--with-android-toolchain', nargs=1,
           help='location of the Android toolchain')
 
 js_option('--with-android-gnu-compiler-version', nargs=1,
           help='GNU compiler version to use')
 
+@depends('--help')
+def min_android_version(_):
+    return '9'
+
+js_option('--with-android-version',
+          nargs=1,
+          help='android platform version',
+          default=min_android_version)
+
+@depends('--with-android-version', min_android_version)
+@imports(_from='__builtin__', _import='ValueError')
+def android_version(value, min_version):
+    if not value:
+        # Someone has passed --without-android-version.
+        die('--with-android-version cannot be disabled.')
+
+    try:
+        version = int(value[0])
+    except ValueError:
+        die('--with-android-version expects an integer value')
+
+    if version < int(min_version):
+        die('--with-android-version must be at least %s (got %s)',
+            min_version, value[0])
+
+    return version
+
 @depends('--with-android-ndk', build_project)
 def ndk(value, build_project):
     if build_project == 'mobile/android' and not value:
         die('You must specify --with-android-ndk=/path/to/ndk when '
             'building mobile/android')
     if value:
         return value[0]
 
 set_config('ANDROID_NDK', ndk)
 add_old_configure_assignment('android_ndk', ndk)
 
+@depends(target, android_version, ndk)
+@checking('for android platform directory')
+def android_platform(target, android_version, ndk):
+    if target.os != 'Android':
+        return
+
+    if 'mips' in target.cpu:
+        target_dir_name = 'mips'
+    else:
+        target_dir_name = target.cpu
+
+    # Not all Android releases have their own platform release. We use
+    # the next lower platform version in these cases.
+    if android_version in (11, 10):
+        platform_version = 9
+    elif android_version in (20, 22):
+        platform_version = android_version - 1
+    else:
+        platform_version = android_version
+
+    platform_dir = os.path.join(ndk,
+                                'platforms',
+                                'android-%s' % platform_version,
+                                'arch-%s' % target_dir_name)
+
+    if not os.path.isdir(platform_dir):
+        die("Android platform directory not found. With the current "
+            "configuration, it should be in %s" % platform_dir)
+
+    return platform_dir
+
+add_old_configure_assignment('android_platform', android_platform)
+
 @depends(target, host, ndk, '--with-android-toolchain',
          '--with-android-gnu-compiler-version')
 @checking('for the Android toolchain directory', lambda x: x or 'not found')
 @imports(_from='mozbuild.shellutil', _import='quote')
 def android_toolchain(target, host, ndk, toolchain, gnu_compiler_version):
     if not ndk:
         return
     if toolchain:

--- a/build/moz.configure/old.configure
+++ b/build/moz.configure/old.configure
@@ -267,17 +267,16 @@ def old_configure_options(*options):
     '--no-create',
     '--prefix',
     '--with-adjust-sdk-keyfile',
     '--with-android-cxx-stl',
     '--with-android-distribution-directory',
     '--with-android-max-sdk',
     '--with-android-min-sdk',
     '--with-android-sdk',
-    '--with-android-version',
     '--with-app-basename',
     '--with-app-name',
     '--with-arch',
     '--with-bing-api-keyfile',
     '--with-branding',
     '--with-crashreporter-enable-percent',
     '--with-cross-lib',
     '--with-debug-label',