Add cross-compilation inputs

Signed-off-by: Cristian Le <git@lecris.dev>

Author: LecrisUT

README.md

@@ -181,6 +181,9 @@ cmake.source-dir = "."
 # DEPRECATED in 0.10; use build.targets instead.
 cmake.targets = ""
 
+# The CMAKE_TOOLCHAIN_FILE used for cross-compilation.
+cmake.toolchain-file = ""
+
 # The versions of Ninja to allow. If Ninja is not present on the system or does
 # not pass this specifier, it will be downloaded via PyPI if possible. An empty
 # string will disable this check.

src/scikit_build_core/builder/builder.py

@@ -231,6 +231,9 @@ def configure(
         python_include_dir = get_python_include_dir()
         numpy_include_dir = get_numpy_include_dir()
 
+        if self.settings.cmake.toolchain_file:
+            cache_config["CMAKE_TOOLCHAIN_FILE"] = self.settings.cmake.toolchain_file
+
         # Classic Find Python
         cache_config["PYTHON_EXECUTABLE"] = sys.executable
         cache_config["PYTHON_INCLUDE_DIR"] = python_include_dir

src/scikit_build_core/resources/scikit-build.schema.json

@@ -102,6 +102,10 @@
           },
           "description": "DEPRECATED in 0.10; use build.targets instead.",
           "deprecated": true
+        },
+        "toolchain-file": {
+          "type": "string",
+          "description": "The CMAKE_TOOLCHAIN_FILE used for cross-compilation."
         }
       }
     },

src/scikit_build_core/settings/skbuild_model.py

@@ -103,6 +103,11 @@ class CMakeSettings:
     DEPRECATED in 0.10; use build.targets instead.
     """
 
+    toolchain_file: Optional[Path] = None
+    """
+    The CMAKE_TOOLCHAIN_FILE used for cross-compilation.
+    """
+
 
 @dataclasses.dataclass
 class SearchSettings: