CHANGES.TXT

Android Emulator changes:
=========================

Versions:

   1.0 => SDK M3 release
   1.1 => SDK M5 release
   1.2 => Internal release (build 72264)
   1.3 => Internal release (build 77780)
   1.4 => Internal release (build 84853)
   1.5 => SDK 0.9_r1
   1.6 => SDK 1.0_r1
   1.7 => SDK 1.0_r2
   1.8 => SDK 1.1
   1.9 => SDK 1.5_r1 (and SDK 1.5_r2)
   1.10 => SDK 1.5_r3
   1.11 => current

==============================================================================
Changes between 1.11 and 1.10

IMPORTANT BUG FIXES:

- Fixed ANDROID_SDK_HOME being ignored on Unix (not Windows). This environment
  variable is used to locate a user's configuration files for the SDK, with a
  default value of ~/.android

==============================================================================
Changes between 1.10 and 1.9

IMPORTANT BUG FIXES:

- Fixed sock_address_init_resolve() in sockets.c to work properly on
  IPv6 capable systems, when the list returned by getaddrinfo() doesn't
  necessarily reflect the simplistic heuristics that were used by the
  previous implementation. On such systems, inter-emulator telephony
  and SMS didn't work properly, as well as certain other network-related
  tasks.

IMPORTANT CHANGES:

- Skins can now provide a button for the "SEARCH" scan-code, simply using
  the "search" label for it.

- A new option '-prop <name>=<value>' can be used to set a system property
  at boot time in the emulated system. This only works for system images
  starting at 1.5_r3, and will be ignored for older ones.

  Note that properties starting with "ro." can only be set once. Moreover,
  all system properties in the system build.prop or local.prop are parsed
  by init before anything else. Any "ro." property in them cannot be
  changed with this option.

- Allow the HTTP proxy implementation to receive chunked encoding data.
  This shall solve problems when talking to Microsoft proxies.

OTHER:

- Allow the SEARCH key-binding (F5) to work on keyboard-less hardware
  configurations (AVDs).

- Fixed a typo which prevented the kernel gdbstub from working properly

- Fixed bad QADD/QDADD/QSUB/QDSUB emulation in the ARM JIT.

- Fixed one minor crash when the Linux OSS audio backend was used with the
  -debug-audio option.

- Fixed emulator tracing bug (basic block address could be wrong). And add
  support for recording native (JNI) calls when profiling.

- Fixed build for platforms where deprecated symbol EAI_NODATA is not
  defined.

- Fix GPS emulation to allow several clients concurrently. There are still
  problems that may be due to changes in the system's framework.

- Added some technical documentation in the docs/ directory.

==============================================================================
Changes between 1.9 and 1.8

IMPORTANT CHANGES:

- Many features have been integrated from upstream QEMU sources, including
  the new TCG code generator used by the ARM translator. This should result
  in slightly faster execution speed on all supported platforms. Another
  benefit is that you no longer require a specific (and obsolete) version
  of GCC to build the emulator.

- The emulator now requires that you specify a virtual device name when
  starting the emulator, prefixed with the '@' sign. For example, to start
  the 'foo' virtual device, type:

      emulator @foo

  Each AVD (Android Virtual Device) corresponds to a directory used to store
  mutable disk images, an optional system image/kernel/sdcard, plus some
  configuration file(s).

  The command-line tool 'android' that comes with the SDK can be used to
  create/list/remove virtual devices on your system.

  Note that the '@<name>' form is a convenience shortcut for '-avd <name>'.
  It is thus possible to place options after the AVD name on your command
  line, as in:

      emulator @foo -verbose -shell

  Finally, when building the Android platform source tree, an AVD name is not
  required and 'emulator' will start a new emulator instance exactly as
  previously.

- A new option '-sysdir <dir>' has been introduced, the interpretation of
  the '-system' option has changed, and '-image <file>' should now be
  considered obsolete. In more details:

  * you should now use '-sysdir <dir>' instead of '-system <dir>' to specify
    the directory where system images will be searched by the emulator
    on startup.

  * you should now use '-system <file>' to indicate which system.img partition
    image to use at startup.

  * you should not use '-system <dir>' or '-image <path>' anymore. However,
    these options are still supported but will print a warning to remind you
    to change your scripts/habits.

  The change was done to reduce confusion as to what these options provide.

- Options '-noaudio', '-nojni', '-noskin' and 'nocache' are deprecated.
  You should use '-no-audio', '-no-jni', '-no-skin' and '-no-cache' instead.

- Option 'initdata' is deprecated, you should use '-init-data' instead.

- Hardware emulation is now limited to the corresponding Android Virtual
  Device's configuration. This means it is now possible to not emulate
  a touch-screen, trackball, dpad, keyboard, modem, etc...

  Note that in the case of the Android build system, all hardware properties
  are enabled by default, so this only affects "normal" virtual devices
  created with the 'android' tool.

- The emulator now supports capturing network packets to a file.
  You can either use the new -tcpdump <file> command-line option, or use
  the new console 'network capture start <file>' command (then use
  'network capture stop' to stop it).

  This captures all ethernet packets on the virtual LAN, so this includes
  ARP, UDP, TCP, etc... The file is in libpcap format and can be opened with
  external tools like WireShark for analysis.

OTHER:

- The file in ~/.android/default.keyset was ignored, unless you used
  '-keyset default' explicitely. It is now loaded automatically when
  available.

- Environment variable ANDROID_SDK_ROOT can be used to specifiy the location
  of the SDK installation path.

- Environment variable ANDROID_SDK_HOME can be used to specify the location
  of the '.android' data directory (which defaults to your $HOME).

- A new console command 'avd name' can be used to query the name of the
  virtual device running in the emulator. Note that it will be '<build>'
  if you run from the Android build system.

  Also, the emulator's window title also displays the AVD name now.

- The option '-memory <size>' has been added. <memory> must be an integer
  specifying the amount of physical RAM in the emulated device in megabytes.
  The default value is 96.

- The '-skindir <path>' option now requires that you specify a '-skin <name>'
  option as well.

- Better handling of Audio on Linux for the EsounD and Alsa backends

- Fullscreen toggle should now work on Windows and OS X. On Linux, the
  toggle will not switch the display resolution anymore (which resulted
  in distorted images).

- Using '-no-audio' no longer disables sound hardware emulation. It simply
  mutes the emulator program on the host.

- The window title bar changes when you toggle persistent trackball mode
  (F6 by default). It will display something like the following:

    "Press F6 to exit trackball mode ..."

  The actual text depends on your key binding configuration. This is to help
  people toggle the mode by accident.

==============================================================================
Changes between 1.7 and 1.6

IMPORTANT BUG FIXES:

- Properly create ~/.android directory when needed.

- Do not leave temporary files in Android app-specific directory on Win32

- Support for HTTP/HTTPS proxies has been considerably improved and should now
  "just work" with a lot more HTTP proxies. In case of problem, use the
  -debug-proxy option to dump debugging data to stderr.

OTHER:

- Trackball emulation has changed. First, the awkward "Control-T" keybinding
  is gone. Instead, you can now:

     - press 'Delete' to show the trackball and have it disappear as soon
       as your release the key.

     - press 'F6' to perform a persistent trackball mode toggle.

  Also, trackball emulation is fixed in rotated/landscape mode now.

- New option '-nand-limits <limits>' allows you to send a signal to a remote
  process when a read or write threshold on flash storage is reached. This is
  only useful for hardcore Android system hackers.

- Fix emulator build on recent Cygwin releases (the -mno-cygwin headers do not
  tolerate the _GNU_SOURCE macro definition anymore)

- Fix Win32 emulator to support SD Card images larger than 2 GiB

- The non-Android build system has been completely rewritten to allow building
  the emulator on Linux x86_64. Also, there is now a single Makefile that
  drives the build in both Android and non-Android modes.

- '-qemu <other-options>' works again

==============================================================================
Changes between 1.6 and 1.5

IMPORTANT CHANGES:

- Emulator now saves the user image in <android>/SDK1.0/

OTHER:

- Get rid of EsounD-related freezes on Linux (again)

- Fix the documentation in -help-audio. '-audio list' doesn't work, one
  needs to call -help-audio-out and -help-audio-in to get the list of valid
  audio backends

- Fix scrollwheel Dpad emulation in rotated mode. before that, using the
  scroll-wheel would always generated Dpad Up/Down events, even when in
  landscape mode.

- Re-enable CPU fault emulation in case of unaligned data access. this was
  previously disabled because it crashed the emulated kernel in previous
  releases.

- The emulator no longer prints an obscure warning when it doesn't find
  the emulator.cfg configuration file in ~/.android.

  'broken configuration file doesn't have a 'window' element'

- Removed a bunch of obsolete options (e.g. -console, -adb-port, etc...)

- Setting the network speed through the console or the -netspeed option will
  properly modify the connectivity icon on the device.

- Setting the GSM voice registration state to 'roaming' in the console will
  properly modify the voice icon on the device

==============================================================================
Changes between 1.5 and 1.4

IMPORTANT BUG FIXES:

- Fix spurious discards of SMS messages when using two emulators.

OTHER:

- Get rid of EsounD-related freezes on Linux (again)

- Fix the documentation in -help-audio. '-audio list' doesn't work; one
  needs to call -help-audio-out and -help-audio-in to get the list of valid
  audio backends

- Fix scrollwheel Dpad emulation in rotated mode. before that, using the
  scroll-wheel would always generated Dpad Up/Down events, even when in
  landscape mode.

- Re-enable CPU fault emulation in case of unaligned data access. This was
  previously disabled because it crashed the emulated kernel in previous
  releases.

==============================================================================
Changes between 1.4 and 1.3

IMPORTANT BUG FIXES:

- fix for audio-related Linux startup freezes when using the 'esd' and 'alsa'
  backends

- the number of audio buffers in the Windows backend has been incremented.
  this gets rid of audio chopiness issues on Vista (and sometimes on XP too)

NEW FEATURES:

NEW CONSOLE COMMANDS:

- new 'geo fix <lontitude> <latitude> [<altitude>]' command allows you to
  send a simple GPS fix to the emulated system, without the headaches of
  NMEA 1083 formatting.

OTHER BUG FIXES:

- fixed the -audio, -audio-in and -audio-out options (the <backend> values
  were sometimes ignored)

REGRESSIONS:

OTHER:

- the transitional '-qemud' option introduced in 1.3 is now gone. its
  behaviour is now the default.

- use the new '-old-system' option if you need to use a 1.4+ emulator binary
  with older system images. if you don't use it, GSM and GPS emulation will
  not work correctly (among other things).

- the obsolete '-oldradio' option is now gone

- on some Unix systems, SIGALRM is blocked by default, so unblock it when
  creating the alarm timer

- the 'esd' and 'alsa' libraries dump a lot of error messages to the console
  by default on Linux. these are now disabled unless you use '-debug audio'

- added the '-help-char-devices' help topic that describe the specification
  of the <device> parameter of options like -serial, -gps, -shell-serial,
  etc...

KNOWN ISSUES:

- no support for video input
- no support for mutable SIM Card emulation yet
- no support for bluetooth
- no support for WiFi

- on some Linux machines, the emulator might get stuck at startup. this
  seems to be related to audio input support. try starting with
  '-audio-in none' or  even '-noaudio' to disable sound, or choose a
  different audio backend by  defining QEMU_AUDIO_DRV to an appropriate
  value (read below).

  you can also select different audio backends for both output and input
  by defining QEMU_AUDIO_OUT_DRV and QEMU_AUDIO_IN_DRV independently.

- on Windows, the emulator takes about 10-15% of the CPU even when the
  emulated system is idle. this is a known issue related to QEMU's internal
  event loop and Winsock. this should be fixed in a future emulator release.

- GPS emulation only if you use the '-qemud' option. this is an experimental
  option that is soon going to be the default. without this option, the
  emulated system will start but GPS emulation will not work.

  for the record, 'qemud' is a serial port multiplexer that is used to
  multiplex several communication channels between the emulator and the
  emulated system, though a single serial port.

==============================================================================
Changes between 1.3 and 1.2

IMPORTANT BUG FIXES:

NEW FEATURES:

- '-audio-in <backend>' allows you to select the audio input backend from the
  command line. this is equivalent to defining QEMU_AUDIO_IN_DRV=<backend>

  '-audio-out <backend>' works for the audio output, and '-audio <backend>'
  will select both input and output at the same time

- '-debug <tags>' has replaced the old '-verbose-<tag1> -verbose-<tag2> ...'
  debugging option. <tags> is a comma-separated list of debug tags
  (see -help-debug-tags for a complete list). you can also use the special
  value 'all' to indicate all debug tags, or prefix a '-' before a tag
  name to disable it. for example:

    -debug all,-audio

  enables all debugging except audio. '-debug-<tag>' still works though.

  note that while '-verbose-<tag>' is deprecated, '-verbose' is still supported
  as an alias to '-debug-init'

- '-keyset <file>' allows you to specific the keyset file to use. the default
  is still ~/.android/default.keyset on Unix. for Windows, use -help-keyset
  to get its default location (which differs between XP and Vista)


NEW CONSOLE COMMANDS:

- the 'geo nmea <sentence>' can be used to send a NMEA 1083 sentence as if
  it came from an emulated GPS unit. NOTE: this doesn't work unless you
  also use the '-qemud' option (see KNOWN ISSUES below)

OTHER BUG FIXES:

- severe color artefact issues when scaling the emulator window < 1.0 were
  fixed.

- fix rare random emulator freezes on Linux by disabling the 'dynticks' timer.

REGRESSIONS:

OTHER:

- the ambiguous '-console' option is now obsolete. use '-shell' instead

- the new '-shell-serial <device>' allows you to specify a device to
  connect a root shell session to the emulated system.

- the '-debug-kernel' option is now known as '-show-kernel' (the -debug-
  prefix is reserved for strict emulator debugging features)

- '-adb-port' has been removed from the list of options. similarly
  '-port <port>' will accept an odd port number, but will print a warning
  that it is using <port>-1 instead.

- MMX is used on x86 to speed up window rescaling.

- a new '-qemud' option is required to have GPS support work in this
  SDK (either through '-gps <device>' or the 'geo nmea <sentence>'
  console command)

  this option is purely experimental and will soon become the default.

KNOWN ISSUES:

- no support for video input
- no support for mutable SIM Card emulation yet
- no support for bluetooth
- no support for WiFi

- on some Linux machines, the emulator might get stuck at startup. this
  seems to be related to audio input support. try starting with
  '-audio-in none' or  even '-noaudio' to disable sound, or choose a
  different audio backend by  defining QEMU_AUDIO_DRV to an appropriate
  value (read below).

  you can also select different audio backends for both output and input
  by defining QEMU_AUDIO_OUT_DRV and QEMU_AUDIO_IN_DRV independently.

- on Windows, the emulator takes about 10-15% of the CPU even when the
  emulated system is idle. this is a known issue related to QEMU's internal
  event loop and Winsock. this should be fixed in a future emulator release.

- GPS emulation only if you use the '-qemud' option. this is an experimental
  option that is soon going to be the default. without this option, the
  emulated system will start but GPS emulation will not work.

  for the record, 'qemud' is a serial port multiplexer that is used to
  multiplex several communication channels between the emulator and the
  emulated system, though a single serial port.

==============================================================================
Changes between 1.2 and 1.1


IMPORTANT BUG FIXES:

- fixed a typo that prevented the F9/F10 keyboard shortcuts from working
  properly, making non-programatically tracing unusable.

- halve the emulator's memory requirements, saving around 130 megabytes
  of memory by changing the way flash images are accessed (we now use
  temporary files instead)

- this emulator binary should be 10% to 20% faster than previous ones on
  the Windows and OS X platforms. for faster boots, you may also want to
  use the -no-boot-anim option described below to speed up the initial
  boot sequence as well on slow machines.

- proper rotation support when using Keypad 7/9 to switch between layouts
  in the default HVGA skin. no need to use Ctrl-PageDown anymore

- the -http-proxy <proxy> option didn't work correctly on Windows (unless
  you were very lucky).

- general socket handling code on Windows has been significantly improved.


NEW FEATURES:

- the console port number of a given emulator instance is now displayed in
  its window's title bar.

- voice/sms are automatically forwarded to other emulator instances running
  on the same machine, as long as you use their console port number as the
  destination phone number.

  for example, if you have two emulator running, the first one will usually
  use console port 5554, and the second one will use port 5556

  then dialing 5556 on the 1st emulator will generate an incoming call on
  the 2nd emulator. you can also hold/unhold calls as well.

  this also works when sending SMS messages from one emulator to the other

- the help system has been totally revamped:

   *  -help              prints a summary of all options and help topics
   *  -help-<option>     prints option-specific help
   *  -help-<topic>      prints various topical help text
   *  -help-all          prints *all* help content at once

- the emulator now tries to automatically detect the host time zone and sends
  it to the emulated system at startup (through the GSM modem). there is also
  a new '-timezone <timezone>' option to be able to specify a different one.

  IMPORTANT: the <timezone> name must be in zoneinfo format, i.e.
             Area/Location, human-friendly abbreviations like "PST" or "CET"
             will not work. examples are:

                 America/Los_Angeles
                 Europe/Paris

- the emulator can now use up to 4 distinct DNS servers (instead of only one).
  by default, they are taken from your system's list, which is obtained by
  calling GetNetworkParams() on Win32, and parsing /etc/resolv.conf on
  Unix.

- a new '-dns-server <server>' option can be used to specify a comma-separated
  list of alternative DNS servers to be used by the emulated system, instead of
  the system's default.

- a new '-scale <fraction>' option allows you to scale the emulator
  window. <fraction> can be a number between 0.1 and 3.0.

  you can also use '-scale <value>dpi', (e.g. '-scale 110dpi') to indicate the
  resolution of your host monitor screen. it will be divided by the emulated
  device's resolution to get an absolute scale.

- a new '-dpi-device <dpi>' option allows you to specific the resolution of
  the emulated device's screen. Note that this is not required: the default
  used is 165, which is the average of several prototypes we've been working
  with.

- add a new '-port <port>' option to specify which port the emulator should
  bind to for the console, instead of letting it guess. <port> must be an
  *even* integer between 5554 and 5584 included. the corresponding ADB port
  will be <port>+1

- [DEPRECATED] add a new '-adb-port <port>' option to specify which port the
  emulator should bind to, instead of letting it guess. <port> must be an odd
  integer between 5555 and 5585 included. the corresponding control console
  will be on <port>-1

  NOTE: -adb-port is deprecated, don't use it, it will probably disappear
  NOTE2: you cannot use both -port and -adb-port at the same time.

- a new '-no-boot-anim' options tells the emulated system to disable the boot
  animation. on slow systems, this can *significantly* reduce the time to
  boot the system in the emulator.

- you can now redefine the emulator's keybinding by writing a 'keyset' file
  and use '-keyset <filename>' to use it when starting the emulator. use
  -help-keyset and -help-keyset-file for all details.

  this allows you to use the emulator effectively on keyboards which don't
  have a keypad, by using different keys..

- you can now toggle between windowed and fullscreen mode at runtime by
  pressing Alt-Enter (only works on Linux at the moment !!)

- use '-audio-out <backend>' and '-audio-in <backend>' to change the output
  and input audio backends used by the emulator. see -help-audio-out and
  -help-audio-in for a list of valid values.

  this is equivalent to setting the QEMU_AUDIO_OUT_DRV and QEMU_AUDIO_IN_DRV
  environment variables.

  use '-audio <backend>' to set both the input and output backends at the
  same time. this is equivalent to setting the QEMU_AUDIO_DRV environment
  variable.


NEW CONSOLE COMMANDS:

- the new 'power' command can be used to control the power/battery state of
  the emulated device.

- the new 'event send' command can be used to send simulated hardware events
  to the Android Linux kernel. each event must be in the form
  <type>:<code>:<value> where:

    <type>  is either an integer or a corresponding string alias
            (use "event types" to see a list of aliases)

    <code>  is either an integer or a corresponding string alias
            that depends on the value of <type> (use "event codes <type>"
            to see a list of these aliases)

    <value> is an integer

  NOTE: Be warned that it is very easy to confuse the kernel about the state
        of emulated hardware by sending the wrong event. An *excellent*
        knowledge of the Linux kernel internals is encouraged before playing
        with "event send".

- the new 'event text <textMessage>' command can be used to simulate
  keypresses of small text messages, where <textMessage> is an utf-8 string.

- the new 'avd stop' and 'avd start' command can be used to stop/start the
  emulation. you can also use 'avd status' to query the current state.

- the new 'window scale <scale>' command allows you to change the scale of
  the emulator window dynamically. <scale> is either an integer followed by
  the 'dpi' suffix (e.g. '120dpi') or a real number between 0.1 and 3.0.

  in the first case, <scale> specifies your monitor dpi; in the second one,
  the new window scale itself.


OTHER BUG FIXES:

- in case of SDL_Init() failure, print the SDL error message.
- disable networking code's logging to /tmp/slirp.log
- the emulator now works with 2GB SD Card files
- the emulator doesn't prevent the screensaver to kick in on OS X anymore
- the -onion and -onion-alpha options now work properly
- a second emulator instance trying to use the same SD Card instance than a
  first one will no longer crash
- it's now possible to properly start the emulator in the background on all
  Unix shells (e.g. "emulator &") without being interrupted/stopped by a
  SIGTTIN or SIGTTOU signal.
- fixed a bug in the SMS emulation that happened when using GSM 7-bit escaped
  characters, i.e. anything in the following: [|]~\{}^
- fixed a small regression where -data <foo> would fail if the file <foo>
  did not exist.


REGRESSIONS:

- the -flash-keys options doesn't work anymore


KNOWN ISSUES:

- no support for video input
- no support for mutable SIM Card emulation yet
- no support for bluetooth
- no support for WiFi

- on some Linux machines, the emulator might get stuck at startup. this
  seems to be related to audio input support. try starting with
  '-audio-in none' or even '-noaudio' to disable sound, or choose a different
  audio backend by defining QEMU_AUDIO_DRV to an appropriate value
  (read below).

  you can also select different audio backends for both output and input
  by defining QEMU_AUDIO_OUT_DRV and QEMU_AUDIO_IN_DRV independently.

- on Windows, the emulator takes about 10-15% of the CPU even when the
  emulated system is idle. this is a known issue related to QEMU's internal
  event loop and Winsock. this should be fixed in a future emulator release.

OTHER:

- you can now use -debug-<component> and/or -debug-no-<component> to
  enable or disable the debug messages of a given emulator component. this
  can be very useful for troubleshooting. for all details, use -help-debug
  and -help-debug-tags

- you can also use '-debug <tags>' where <tags> is a comma-separated list
  of component names, optionally prefixed by a single '-'. see -help-debug
  and -help-debug-tags for all details

- you can now define the ANDROID_VERBOSE environment variable as a list
  of "debug" items (each <item> corresponds to a -debug-<item> option).
  for example, defining:

     ANDROID_VERBOSE=socket,keys

  is equivalent to using "-debug socket,keys" when invoking the emulator

- as a special case, -debug-slirp enables logging of the router/firewall
  operations to a temporary file (e.g. /tmp/android/slirp.log). you can
  also specify a logging bitmask with the ANDROID_SLIRP_LOGMASK environment
  variable (the default is a mask of 7).

- removed many obsolete / unused source files from the repository. also
  performed a rather heavy cleanup of the sources to make them somewhat
  more manageable.

- integrate dynticks support from upstream QEMU depot. this only allows one
  to provide more precise timing accuracy in the guest under Linux.
  (NOTE: disabled in the source code, since it seems that it freezes
  the emulator sometimes)

- audio input is now working on OS X, Windows and Linux. on Linux, there
  are four different backends supported: EsounD, ALSA, OSS and SDL. they
  are accessed through dlopen/dlsym, which means that the emulator binary
  will run on any system.

  you can specify a given backend by defining the QEMU_AUDIO_DRV environment
  variable to one of these values:

    alsa
    esd
    sdl
    oss
    none

  note that the "sdl" audio backend is the most compatible, but doesn't
  support audio input at all !!

- a new option '-cpu-delay <delay>' can be used to slow down the CPU
  emulation. the <delay> is an integer between 0 and 1000. note that it
  doesn't necessarily scale linearly with effective performance.

  the delay process is not exactly deterministic. this is just a hack that
  may disappear or be completely re-implemented in the future

- some new "gsm" and "sms" subcommands were added to the control console.
  they are used internally by the voice/sms auto-forwarder and are probably
  not very useful to typical developers

- some code has been added to support save/restore of the AVD state to/from
  a file. however this is not properly tested yet, and requires that you
  use exactly the same options and disk images when reloading the AVD state.

- added a new -cache <file> option to specify the cache partition image
  file. the default is to use a temporary file instead

- added a new -report-console <socket> option to be able to report the
  automatically assigned console port to a remote third-party (e.g. a
  script) before starting the emulation. see the output of -help for all
  the details

- (only useful to Android engineers)
  the audio sub-system is now compiled in its own static library (called
  libqemu-audio.a), which gets copied to the Android "prebuilt/Linux/qemu"
  directory. this is done to avoid forcing all developers to install various
  development packages on Linux, as well as all build servers. there is also
  now a script named "distrib/update-audio.sh" which will update the depot
  file automatically for you: call it whenever you change the audio sources.