Infer python version from Makefile.envs in PyO3 (#19)

Instead of hardcoding the Python version, use
`PYO3_CROSS_PYTHON_VERSION` env variable, which [PyO3 uses to find the
correct Python include/lib
paths](https://pyo3.rs/main/building-and-distribution#cross-compiling).

Also removed pyo3_config.ini file. Otherwise, the config file always
take precedence.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Changed
+
+- `pyo3_config_file` is no longer available in `pyodide config` command.
+  Pyodide now sets `PYO3_CROSS_PYTHON_VERSION`, `PYO3_CROSS_LIB_DIR` to specify the cross compilation environment
+  for PyO3.
+  [#19](https://github.com/pyodide/pyodide-build/pull/19)
+
 ## [0.28.0] - 2024/08/14
 
 - `pyodide xbuildenv` subcommand is now publicly available.

pyodide_build/cli/config.py

@@ -11,7 +11,6 @@
     "python_version": "PYVERSION",
     "rustflags": "RUSTFLAGS",
     "cmake_toolchain_file": "CMAKE_TOOLCHAIN_FILE",
-    "pyo3_config_file": "PYO3_CONFIG_FILE",
     "rust_toolchain": "RUST_TOOLCHAIN",
     "cflags": "SIDE_MODULE_CFLAGS",
     "cxxflags": "SIDE_MODULE_CXXFLAGS",

pyodide_build/config.py

@@ -143,6 +143,7 @@ def to_env(self) -> dict[str, str]:
     "pyminor": "PYMINOR",
     "pyo3_cross_include_dir": "PYO3_CROSS_INCLUDE_DIR",
     "pyo3_cross_lib_dir": "PYO3_CROSS_LIB_DIR",
+    "pyo3_cross_python_version": "PYO3_CROSS_PYTHON_VERSION",
     "pyodide_emscripten_version": "PYODIDE_EMSCRIPTEN_VERSION",
     "pyodide_jobs": "PYODIDE_JOBS",
     "pyodide_root": "PYODIDE_ROOT",
@@ -161,7 +162,6 @@ def to_env(self) -> dict[str, str]:
     "sysconfig_name": "SYSCONFIG_NAME",
     "targetinstalldir": "TARGETINSTALLDIR",
     "cmake_toolchain_file": "CMAKE_TOOLCHAIN_FILE",
-    "pyo3_config_file": "PYO3_CONFIG_FILE",
     "meson_cross_file": "MESON_CROSS_FILE",
     "cflags_base": "CFLAGS_BASE",
     "cxxflags_base": "CXXFLAGS_BASE",
@@ -192,7 +192,6 @@ def to_env(self) -> dict[str, str]:
 DEFAULT_CONFIG: dict[str, str] = {
     # Paths to toolchain configuration files
     "cmake_toolchain_file": str(TOOLS_DIR / "cmake/Modules/Platform/Emscripten.cmake"),
-    "pyo3_config_file": str(TOOLS_DIR / "pyo3_config.ini"),
     "meson_cross_file": str(TOOLS_DIR / "emscripten.meson.cross"),
     # Rust-specific configuration
     "rustflags": "-C link-arg=-sSIDE_MODULE=2 -C link-arg=-sWASM_BIGINT -Z link-native-libraries=no",
@@ -213,8 +212,9 @@ def to_env(self) -> dict[str, str]:
     "cxxflags": "$(CXXFLAGS_BASE)",
     "ldflags": "$(LDFLAGS_BASE) -s SIDE_MODULE=1",
     # Rust-specific configuration
-    "pyo3_cross_lib_dir": "$(CPYTHONINSTALL)/lib",
+    "pyo3_cross_lib_dir": "$(CPYTHONINSTALL)/sysconfigdata",  # FIXME: pyodide xbuildenv stores sysconfigdata here
     "pyo3_cross_include_dir": "$(PYTHONINCLUDE)",
+    "pyo3_cross_python_version": "$(PYMAJOR).$(PYMINOR)",
     # Misc
     "stdlib_module_cflags": "$(CFLAGS_BASE) -I$(PYTHONINCLUDE) -I Include/ -I. -IInclude/internal/",  # TODO: remove this
     # Paths to build dependencies