feat: Android improvements needed for building NumPy and related packages (#2695)

* Use auditwheel on Android

* Add auditwheel command to defaults

* pkgconfig fixes

* Pre-import ctypes before monkey-patching in _cross_venv

* Set PKG_CONFIG and PKG_CONFIG_RELOCATE_PATHS variables

* Initial attempt at using mzakharo/android-gfortran

* Switch to using termux/ndk-toolchain-clang-with-flang

* Move PKG_CONFIG variables from build_env to android_env

* Simplify flang installation

* Add cross build files for NumPy

* Add ldpaths entry for libomp

* Add `--rm` to docker command line

* Make Rust and Fortran shims consistent

* Update documentation

* Default to API level 24 on all Python versions

* Clarify comments

* Cleanups

* Fix tests:
* Set up Android env after installing pkgconf
* Add tests for successfully using an older API level
* Previous commit's auditwheel failure is fixed in the auditwheel PR

* Update how-it-works diagram

* Add tests for repair errors

* Add more repair tests

* Add test for Meson and Fortran

* Add test for cross build files

* Improve test_api_level error message

* Add xbuild-files option

* use pypa/auditwheel@main

* Remove dependencies which are no longer needed

* Fix README

* Update to auditwheel 6.7.0

* Fix compatibility with pkgconf 2.5.1.post2

* Documentation clarifications

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

* Fortran shim improvements

* Add Jinja variables to new_meson_project

* Update run_example_ci_configs for changed new_meson_project signature

* Add missing dependency to run_example_ci_configs

---------

Co-authored-by: mayeut <mayeut@users.noreply.github.com>
Co-authored-by: Joe Rickerby <joerick@mac.com>

test/test_projects/meson.py

@@ -22,6 +22,7 @@ archs = ["auto64"]
 
 MESON_BUILD_TEMPLATE = r"""
 project('spam', 'c',
+  {{ project_args_add | indent(2) }}
   version: '0.1.0',
   default_options: ['warning_level=2'],
 )
@@ -30,6 +31,7 @@ py = import('python').find_installation(pure: false)
 
 py.extension_module('spam',
   'spam.c',
+  {{ extension_args_add | indent(2) }}
   install: true,
 )
 """
@@ -39,6 +41,8 @@ def new_meson_project(
     *,
     spam_c_top_level_add: str = "",
     spam_c_function_add: str = "",
+    project_args_add: str = "",
+    extension_args_add: str = "",
 ) -> TestProject:
     project = TestProject()
 
@@ -54,6 +58,8 @@ def new_meson_project(
         {
             "spam_c_top_level_add": spam_c_top_level_add,
             "spam_c_function_add": spam_c_function_add,
+            "project_args_add": project_args_add,
+            "extension_args_add": extension_args_add,
         }
     )