fix(ci): also unset LDFLAGS/CFLAGS for cross-compilation

Conda's cross-compilation toolchain sets LDFLAGS with
-L$CONDA_PREFIX/lib pointing to host x86_64 libraries. CMake
picks up LDFLAGS from the environment, causing lld to find
incompatible libgcc_s.so.1. Strip all conda compiler flags
since our toolchain.cmake provides the correct settings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 16bit-ykiko

.github/workflows/test-cmake.yml

@@ -81,14 +81,14 @@ jobs:
         shell: bash
         run: |
           ENV="${{ matrix.pixi_env || 'default' }}"
-          pixi run -e "$ENV" -- env -u LIBRARY_PATH \
+          pixi run -e "$ENV" -- env -u LIBRARY_PATH -u LDFLAGS -u CFLAGS -u CXXFLAGS -u CPPFLAGS \
             cmake -B "build/${{ matrix.build_type }}" -G Ninja \
             -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} \
             -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain.cmake \
             -DCLICE_ENABLE_TEST=ON \
             -DCLICE_CI_ENVIRONMENT=OFF \
             "-DCLICE_TARGET_TRIPLE=${{ matrix.target_triple }}"
-          pixi run -e "$ENV" -- env -u LIBRARY_PATH \
+          pixi run -e "$ENV" -- env -u LIBRARY_PATH -u LDFLAGS -u CFLAGS -u CXXFLAGS -u CPPFLAGS \
             cmake --build "build/${{ matrix.build_type }}"
 
       - name: Upload cross-compiled binaries