mlx: set PYPI_RELEASE=1 to avoid a dev version (#1935)

setup.py's get_version() only emits the clean tag version (e.g. 0.32.2)
when PYPI_RELEASE=1; otherwise it always appends .devYYYYMMDD+<git-hash>,
even when building from an exact, unpatched v0.32.2 checkout. Applies to
both the mlx frontend and mlx-cpu backend packages, which share the same
setup.py (published so far: 0.32.2.dev20260914+1f8e74e for both).

Author: luhenry

.github/workflows/build-mlx.yml

@@ -75,6 +75,10 @@ jobs:
           # avoids patching setup.py.
           export CMAKE_ARGS="-DMLX_BUILD_METAL=OFF -DMLX_BUILD_CUDA=OFF -DCMAKE_INSTALL_LIBDIR=lib -G Ninja"
           export MLX_BUILD_BACKEND_PACKAGE=1
+          # setup.py's get_version() only emits the clean tag version when
+          # PYPI_RELEASE=1; otherwise it appends .devYYYYMMDD+<git-hash>
+          # regardless of building from an exact, unpatched tag checkout.
+          export PYPI_RELEASE=1
           "$PY" -m build -w
 
           auditwheel repair dist/mlx_cpu-*.whl --plat manylinux_2_39_riscv64 --wheel-dir /output
@@ -130,6 +134,8 @@ jobs:
           cd /mlx
           export CMAKE_ARGS="-DMLX_BUILD_METAL=OFF -DMLX_BUILD_CUDA=OFF -DCMAKE_INSTALL_LIBDIR=lib -G Ninja"
           export MLX_BUILD_FRONTEND_PACKAGE=1
+          # See the build_backend job for why this is needed.
+          export PYPI_RELEASE=1
           "$PY" -m build -w
 
           # libmlx.so ships separately in mlx-cpu, so it (and anything only reachable