build/tools.atree: Move x86-specific changes to tools.x86.atree

Unfortunately, the latest x86-specific changes to tools.atree break
internal Android builds that depend on this file.

This change moves the changes to a different file that is only
parsed for x86-specific SDK builds (sdk_x86-eng).

It depends on https://review.source.android.com/#change,21957
to allow the AOSP build to pick up tools.x86.atree properly.

Change-Id: I163d7fb43aa06609d9b0e4bfbaf56311958ea25e
diff --git a/build/tools.atree b/build/tools.atree
index db3367c..208f6f7 100644
--- a/build/tools.atree
+++ b/build/tools.atree
@@ -40,11 +40,10 @@
 bin/zipalign     tools/zipalign
 
 # emulator
-bin/emulator tools/emulator-arm
-bin/emulator-x86   tools/emulator-x86
+# note: the following line should better to to tools.arm.atree
+# but is kept here to avoid breaking internal branches.
+bin/emulator  tools/emulator-arm
 sdk/emulator/snapshot/snapshots.img tools/lib/emulator/snapshots.img
-usr/share/pc-bios/bios.bin   tools/lib/pc-bios/bios.bin
-usr/share/pc-bios/vgabios-cirrus.bin   tools/lib/pc-bios/vgabios-cirrus.bin
 
 # Java-Based SDK Tools
 bin/ddms            tools/ddms
diff --git a/build/tools.x86.atree b/build/tools.x86.atree
new file mode 100644
index 0000000..3b64886
--- /dev/null
+++ b/build/tools.x86.atree
@@ -0,0 +1,22 @@
+#
+# Copyright (C) 2011 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Additionnal target-specific definitions for tools.atree
+
+# emulator
+bin/emulator-x86                       tools/emulator-x86
+usr/share/pc-bios/bios.bin             tools/lib/pc-bios/bios.bin
+usr/share/pc-bios/vgabios-cirrus.bin   tools/lib/pc-bios/vgabios-cirrus.bin