Use Bazel select for linker options

Guards against unknown linker option errors by selecting required
linker options for nanobind only on macOS, where they are relevant.

Other changes:
* Bump cibuildwheel action to v2.12.0
* Bump Bazel for aarch64 linux wheels to 6.0.0
* Remove C++17 flag from build files since it is present in setup.py `bazel build` command
* Bump nanobind commit to current HEAD (TBD: Bump to next stable release)

Author: nicholasjng

.github/install_bazel.sh

@@ -5,7 +5,7 @@ if ! bazel version; then
   fi
   echo "Installing wget and downloading $arch Bazel binary from GitHub releases."
   yum install -y wget
-  wget "https://github.com/bazelbuild/bazel/releases/download/5.2.0/bazel-5.2.0-linux-$arch" -O /usr/local/bin/bazel
+  wget "https://github.com/bazelbuild/bazel/releases/download/6.0.0/bazel-6.0.0-linux-$arch" -O /usr/local/bin/bazel
   chmod +x /usr/local/bin/bazel
 else
   # bazel is installed for the correct architecture

.github/workflows/wheels.yml

@@ -46,12 +46,11 @@ jobs:
           platforms: all
 
       - name: Build wheels on ${{ matrix.os }} using cibuildwheel
-        uses: pypa/cibuildwheel@v2.11.4
+        uses: pypa/cibuildwheel@v2.12.0
         env:
           CIBW_BUILD: 'cp38-* cp39-* cp310-* cp311-*'
           CIBW_SKIP: "*-musllinux_*"
           CIBW_TEST_SKIP: "*-macosx_arm64"
-          # TODO: Build ppc64le using some other trick
           CIBW_ARCHS_LINUX: x86_64 aarch64
           CIBW_ARCHS_MACOS: x86_64 arm64
           CIBW_ARCHS_WINDOWS: AMD64

bazel/benchmark_deps.bzl

@@ -48,7 +48,7 @@ def benchmark_deps():
         git_repository(
             name = "nanobind",
             remote = "https://github.com/wjakob/nanobind.git",
-            commit = "2894c92475ccfd38df31daf3f12f915bbd9d3a9d",
+            commit = "947fbb071eca282e6350402c0a23800502a1644f",
             build_file = "@//bindings/python:nanobind.BUILD",
             recursive_init_submodules = True,
         )

bindings/python/google_benchmark/BUILD

@@ -15,7 +15,6 @@ py_extension(
     copts = [
         "-fexceptions",
         "-fno-strict-aliasing",
-        "-std=c++17",
     ],
     features = [
         "-use_header_modules",

bindings/python/nanobind.BUILD

@@ -1,3 +1,10 @@
+
+config_setting(
+    name = "macos",
+    constraint_values = ["@platforms//os:macos"],
+    visibility = [":__subpackages__"],
+)
+
 cc_library(
     name = "nanobind",
     hdrs = glob(
@@ -30,11 +37,13 @@ cc_library(
     ],
     copts = [
         "-fexceptions",
-        "-std=c++17", # requires C++17
-        "-Os",  # size optimization option for nanobind
+        "-Os",  # size optimization
         "-flto", # enable LTO
     ],
-    linkopts = ["-undefined suppress", "-flat_namespace", "-flto"],
+    linkopts = select({
+        ":macos": ["-undefined suppress", "-flat_namespace"],
+        "//conditions:default": [],
+    }),
     includes = ["include", "ext/robin_map/include"],
     deps = ["@python_headers"],
     visibility = ["//visibility:public"],

setup.py

@@ -88,7 +88,7 @@ def bazel_build(self, ext):
             ext.bazel_target,
             "--symlink_prefix=" + os.path.join(self.build_temp, "bazel-"),
             "--compilation_mode=" + ("dbg" if self.debug else "opt"),
-            "--cxxopt=-std=c++17",  # C++17
+            "--cxxopt=-std=c++17",  # required by nanobind
         ]
 
         if IS_WINDOWS: