Allow to build packages on device

[ghost]

Set of compatibility patches that makes our build system partially usable in Termux.

Related issue: #1756

Proof of concept:

---

Behaviour changes for all builds:

• Now will be stripped binaries located only in bin, lib or libexec.

• When build-package.sh is called recursively, it won't pass TERMUX_ARCH with command line argument but will do this through exported environment variable.

---

Packages that delete stuff from TERMUX_PREFIX in build process. If for some packages that behaviour is acceptable, the others may delete user configuration files and critical runtime libraries.

These packages have stubs in their build.sh to prevent building on device. E.g. trying to build perl will result in following:

$ ./build-package.sh -f perl
termux - building perl for arch aarch64...
Downloading http://www.cpan.org/src/5.0/perl-5.30.0.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 17.0M  100 17.0M    0     0  9985k      0  0:00:01  0:00:01 --:--:-- 9985k
Downloading https://github.com/arsv/perl-cross/releases/download/1.3/perl-cross-1.3.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   611    0   611    0     0   1486      0 --:--:-- --:--:-- --:--:--  1486
100  103k  100  103k    0     0  60354      0  0:00:01  0:00:01 --:--:-- 79442
ERROR: Package 'perl' is not safe for on-device builds.

• aapt
• apache2
• apt
• boost
• busybox
• dialog
• ecj
• emacs
• espeak
• fzf
• gawk
• gcal
• git
• golang
• jsoncpp
• ldc
• libbz2
• librsync
• libtalloc
• libunwind
• libvpx
• mariadb
• mpd
• ncurses
• nginx
• openjpeg
• openssh
• openssl
• pastebinit
• perl
• picolisp
• pkg-config
• postgresql
• privoxy
• proxychains-ng
• radare2
• texlive-tlmgr
• vim
• vim-python
• xvidcore
• zsh

[finagolfin]

Wow, great work, looking forward to trying this out. 😄

Any input on this old CMake issue also, #151? I can look into that and try submitting a patch to change it, if @fornwall and the Termux devs agree to change it.

I'll also test out this pull and help get it done.

[finagolfin]

Hmm, this ties into the issue I raised with #151, most packages that use this will likely require setting this on-device too.

[ghost]

-DCMAKE_SYSTEM_NAME=Android seems require option for standalone toolchain.

File ./share/cmake-3.14/Modules/Platform/Android-Determine.cmake:

if(NOT IS_DIRECTORY "${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}")
    message(FATAL_ERROR
      "Android: The standalone toolchain directory specified by CMAKE_ANDROID_STANDALONE_TOOLCHAIN:\n"
      "  ${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}\n"
      "does not exist."
      )
...
  if(NOT EXISTS "${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}/sysroot/usr/include/android/api-level.h")
    message(FATAL_ERROR
      "Android: The standalone toolchain directory specified by CMAKE_ANDROID_STANDALONE_TOOLCHAIN:\n"
      "  ${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}\n"
      "does not contain a sysroot with a known layout.  The file:\n"
      "  ${CMAKE_ANDROID_STANDALONE_TOOLCHAIN}/sysroot/usr/include/android/api-level.h\n"
      "does not exist."
      )

So having CMAKE_SYSTEM_NAME=Android on device will require patching CMake.

[finagolfin]

OK, someone mentioned that on that issue a couple years ago. I'm already proposing patching CMake to make sure CMake sets that variable to Android on Termux, I will look into what else is necessary, such as modifying that file you quote also.

Once that's done, this won't need to be repeated for the on-device build. I just want to know from you and @fornwall that you'd accept a CMake patch to change that, as Fredrik seemed to want it a couple years ago, before I look into submitting a pull for CMake here.

You mentioned earlier that some packages aren't building with the on-device clang, some of those could be because this CMake variable is not set on-device.

[finagolfin]

Thanks for all the work on this, I will try this pull out in a fresh Termux install. Regarding all those packages that delete files, I looked at some of them and they mostly seem to delete files that were probably installed by a previous version of that same package, before updating to the new ones.

There's two ways I see to handle this:

• Tell the dev to backup any files he wants in $TERMUX_PREFIX, as a newly built package may delete his config files or other changes.
• Put in some way to deal with merging the old files with the new ones, possibly on a package-by-package basis and by checking for the new $TERMUX_ON_DEVICE_BUILD variable. We could push this for later and simply mass-label all those packages as non-buildable on device for now, and I can slowly fix them to work on-device over time.

Let me know what you think.

[ghost]

For now these packages can be just excluded from on-device build. If one of these packages is a dependency, it can be installed with apt and build-package.sh will skip it.