Add SKBUILD_CMAKE_DEFINE to pass CMAKE_PREFIX_PATH to CMake

scikit-build-core may not pass environment variables to CMake properly.
Use SKBUILD_CMAKE_DEFINE to explicitly pass CMAKE_PREFIX_PATH as a CMake define.

Author: jeongseok-meta

pyproject-pypi.toml.j2

@@ -261,7 +261,9 @@ before-build = """
 pip install scikit-build-core pybind11 setuptools-scm
 pip install "torch>=2.8.0,<2.9" --index-url https://download.pytorch.org/whl/cpu
 """
-environment = { CMAKE_PREFIX_PATH = "{project}/.pixi/envs/default", MOMENTUM_BUILD_WITH_FBXSDK = "OFF" }
+# Pass CMAKE_PREFIX_PATH via both environment and cmake.define
+# The {project} placeholder is expanded by cibuildwheel
+environment = { CMAKE_PREFIX_PATH = "{project}/.pixi/envs/default", MOMENTUM_BUILD_WITH_FBXSDK = "OFF", SKBUILD_CMAKE_DEFINE = "CMAKE_PREFIX_PATH={project}/.pixi/envs/default" }
 
 [tool.cibuildwheel.windows]
 # Disable build isolation to ensure CMAKE_PREFIX_PATH is properly passed to CMake
@@ -271,5 +273,7 @@ before-build = """
 pip install scikit-build-core pybind11 setuptools-scm
 pip install "torch>=2.8.0,<2.9" --index-url https://download.pytorch.org/whl/cpu
 """
-environment = { CMAKE_PREFIX_PATH = "{project}/.pixi/envs/default", MOMENTUM_BUILD_WITH_FBXSDK = "OFF" }
+# Pass CMAKE_PREFIX_PATH via both environment and cmake.define
+# The {project} placeholder is expanded by cibuildwheel
+environment = { CMAKE_PREFIX_PATH = "{project}/.pixi/envs/default", MOMENTUM_BUILD_WITH_FBXSDK = "OFF", SKBUILD_CMAKE_DEFINE = "CMAKE_PREFIX_PATH={project}/.pixi/envs/default" }
 {% endif %}