feat: add support for building Android wheels (#2349)

* Add Android to resource files

* Add Android to miscellaneous places

* Add Android documentation

* Docs cleanups

* Add Android platform module; implement top-level structure and target Python installation

* Implement setup_env and build_wheel

* lru-dict build working

* Alter prefix in sysconfigdata file; fix various issues with FLAGS variables

* Implement Android testing

* Add type annotations to _cross_venv

* Revert Python 3.8 to pip 25.0.1

* Make test-sources required on Android

* Add Android integration tests

* Test cleanups

* Add test of all available Python versions

* Update test-sources and test-command behavior to match iOS

* Documentation cleanups

* Replace Builder class with a set of global functions

* Rename "env" to "build_env"

* Remove Chaquopy repository from default pip command line

* Move native_platform to platforms module

* Fix parse_config_settings

Co-authored-by: Joe Rickerby <joerick@mac.com>

* Add unit tests for parse_config_settings and arch_synonym

* Make `shell_prepared` arguments keyword-only, and add tests for the commands that use it

* Replace `importlib.util.spec_from_file_location` with `runpy.run_path`

* Use python-build-standalone

* Update Android Python

* Enable KVM in Linux CI

* Move KVM code to test_android.py

* Use Java 17 on Azure

* Install emulator if necessary before running -accel-check

* Free up additional disk space on Linux runners

* Add sudo

* Skip emulator tests on CI platforms that don't support it

* Download Android Python from Maven Central

* Free up more disk space on Linux runners

* fix: minor fixups

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

* Set sysconfig._BASE_PREFIX to support sysconfig.get_path("include")

* Get ANDROID_API_LEVEL from the build environment, not cibuildwheel's own environment

* Correct relative path of test-sources

* Pass a CMake toolchain file to the build

* Add "repair" step which adds libc++ to the wheel when necessary

* Add missing needs_emulator decorator

* Provide useful error message if ANDROID_HOME is not set

* Remove use of HOST environment variable

* Update to Python 3.15.5

* Fix PyLint warnings, clarify comment

* Group common arguments into a dataclass

* Handle environment variables containing newlines

* Discourage the use of `pytest` test commands without `python -m`

* Use single quotes in user-visible messages

* Improve testing documentation

* Pass wheel filename to `log.build_end`

* In GitHub Actions example, skip Android tests on macOS

* Correct relative paths in `patchelf --set-rpath`

* Clarify `test-sources` docs

* Update to Python 3.13.5+20250722.214220

---------

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>
Co-authored-by: Joe Rickerby <joerick@mac.com>
Co-authored-by: Henry Schreiner <henryschreineriii@gmail.com>

unit_test/main_tests/main_options_test.py

@@ -7,7 +7,7 @@ import pytest
 
 from cibuildwheel.__main__ import main
 from cibuildwheel.environment import ParsedEnvironment
-from cibuildwheel.frontend import _split_config_settings
+from cibuildwheel.frontend import _split_config_settings, parse_config_settings
 from cibuildwheel.options import BuildOptions, _get_pinned_container_images
 from cibuildwheel.selector import BuildSelector, EnableGroup
 from cibuildwheel.util import resources
@@ -289,7 +289,9 @@ def test_build_verbosity(
 
 @pytest.mark.parametrize("platform_specific", [False, True])
 def test_config_settings(platform_specific, platform, intercepted_build_args, monkeypatch):
-    config_settings = 'setting=value setting=value2 other="something else"'
+    config_settings = (
+        'setting=value setting=value2 triplet=1 triplet=2 triplet=3 other="something else"'
+    )
     if platform_specific:
         monkeypatch.setenv("CIBW_CONFIG_SETTINGS_" + platform.upper(), config_settings)
         monkeypatch.setenv("CIBW_CONFIG_SETTINGS", "a=b")
@@ -304,8 +306,16 @@ def test_config_settings(platform_specific, platform, intercepted_build_args, mo
     assert _split_config_settings(config_settings) == [
         "-Csetting=value",
         "-Csetting=value2",
+        "-Ctriplet=1",
+        "-Ctriplet=2",
+        "-Ctriplet=3",
         "-Cother=something else",
     ]
+    assert parse_config_settings(config_settings) == {
+        "setting": ["value", "value2"],
+        "triplet": ["1", "2", "3"],
+        "other": "something else",
+    }
 
 
 @pytest.mark.parametrize(
@@ -494,7 +504,8 @@ def test_defaults(platform, intercepted_build_args):
     if isinstance(repair_wheel_default, list):
         repair_wheel_default = " && ".join(repair_wheel_default)
     assert build_options.repair_command == repair_wheel_default
-    assert build_options.build_frontend is None
+    assert build_options.build_frontend.name == "build"
+    assert build_options.build_frontend.args == ()
 
     if platform == "linux":
         assert build_options.manylinux_images