move platforms under @zig_cc//platform:

README.md

@@ -114,9 +114,6 @@ The path to Bazel toolchains is `@zig_sdk//:<toolchain>_toolchain`. It should
 be moved to `@zig_sdk//toolchain:<toolchain>` or similar; so the user-facing
 targets are in their own namespace.
 
-Likewise, platforms are `@zig_sdk//:<platform>_platform`, and should be moved
-to `@zig_sdk//:platform:<platform>`.
-
 ## OSX: sysroot
 
 For non-trivial programs (and for all darwin/arm64 cgo programs) MacOS SDK may
@@ -164,7 +161,7 @@ may apply to aarch64, but the author didn't find a need to test it (yet).
 ## build & run linux cgo + glibc
 
 ```
-$ bazel build --platforms @zig_sdk//:linux_amd64_platform //test/go:go
+$ bazel build --platforms @zig_sdk//platform:linux_amd64 //test/go:go
 $ file bazel-out/k8-opt-ST-d17813c235ce/bin/test/go/go_/go
 bazel-out/k8-opt-ST-d17813c235ce/bin/test/go/go_/go: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.0.0, Go BuildID=redacted, with debug_info, not stripped
 $ bazel-out/k8-opt-ST-d17813c235ce/bin/test/go/go_/go
@@ -176,7 +173,7 @@ hello, world
 ```
 $ bazel test \
     --config=qemu-aarch64 \
-    --platforms @zig_sdk//:linux_arm64_platform \
+    --platforms @zig_sdk//platform:linux_arm64 \
     --extra_toolchains @zig_sdk//:linux_arm64_musl_toolchain //test/...
 ...
 INFO: Build completed successfully, 10 total actions
@@ -186,7 +183,7 @@ INFO: Build completed successfully, 10 total actions
 ## macos cgo
 
 ```
-$ bazel build --platforms @zig_sdk//:darwin_amd64_platform //test/go:go
+$ bazel build --platforms @zig_sdk//platform:darwin_amd64 //test/go:go
 ...
 $ file bazel-out/k8-opt-ST-d17813c235ce/bin/test/go/go_/go
 bazel-out/k8-opt-ST-d17813c235ce/bin/test/go/go_/go: Mach-O 64-bit x86_64 executable, flags:<NOUNDEFS|DYLDLINK|TWOLEVEL|PIE|HAS_TLV_DESCRIPTORS>

ci/test

@@ -18,7 +18,7 @@ while read -r action platform toolchain config; do
     fi
 
     args+=(\
-        --platforms "@zig_sdk//:${platform}_platform" \
+        --platforms "@zig_sdk//platform:${platform}" \
         --extra_toolchains "@zig_sdk//:${toolchain}_toolchain" \
         //test/... \
     )

toolchain/defs.bzl

@@ -264,6 +264,11 @@ def _zig_repository_impl(repository_ctx):
         content = _fcntl_h,
     )
 
+    repository_ctx.symlink(
+        Label("//toolchain/platform:BUILD"),
+        "platform/BUILD",
+    )
+
     repository_ctx.template(
         "BUILD.bazel",
         Label("//toolchain:BUILD.sdk.bazel"),
@@ -380,6 +385,7 @@ def zig_build_macro(absolute_path, zig_include_root):
             toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
         )
 
+def declare_platforms():
     # create @zig_sdk//{os}_{arch}_platform entries with zig and go conventions
     for zigcpu, gocpu in (("x86_64", "amd64"), ("aarch64", "arm64")):
         for bzlos, oss in {"linux": ["linux"], "macos": ["macos", "darwin"]}.items():
@@ -389,10 +395,10 @@ def zig_build_macro(absolute_path, zig_include_root):
                     "@platforms//cpu:{}".format(zigcpu),
                 ]
                 native.platform(
-                    name = "{os}_{zigcpu}_platform".format(os = os, zigcpu = zigcpu),
+                    name = "{os}_{zigcpu}".format(os = os, zigcpu = zigcpu),
                     constraint_values = constraint_values,
                 )
                 native.platform(
-                    name = "{os}_{gocpu}_platform".format(os = os, gocpu = gocpu),
+                    name = "{os}_{gocpu}".format(os = os, gocpu = gocpu),
                     constraint_values = constraint_values,
                 )

toolchain/platform/BUILD

@@ -0,0 +1,3 @@
+load("@bazel-zig-cc//toolchain:defs.bzl", "declare_platforms")
+
+declare_platforms()