bazel: Add @platforms//os:none to constraints

Bug: 348008794
Change-Id: Ib43cb3b2bb8ec8f2557c8c230b32501a83e4e1d2
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/216812
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Reviewed-by: Armando Montanez <amontanez@google.com>
Pigweed-Auto-Submit: Ted Pudlik <tpudlik@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/targets/rp2040/BUILD.bazel b/targets/rp2040/BUILD.bazel
index 6e6805b..b562acd 100644
--- a/targets/rp2040/BUILD.bazel
+++ b/targets/rp2040/BUILD.bazel
@@ -25,6 +25,7 @@
         "@pigweed//pw_build/constraints/rtos:freertos",
         "@pigweed//pw_interrupt_cortex_m:backend",
         "@pigweed//targets/rp2040:freertos_config_cv",
+        "@platforms//os:none",
 
         # For toolchain selection.
         "@platforms//cpu:armv6-m",
diff --git a/targets/stm32f429i_disc1_stm32cube/BUILD.bazel b/targets/stm32f429i_disc1_stm32cube/BUILD.bazel
index b6bdd04..3f905b0 100644
--- a/targets/stm32f429i_disc1_stm32cube/BUILD.bazel
+++ b/targets/stm32f429i_disc1_stm32cube/BUILD.bazel
@@ -26,6 +26,7 @@
         "@pigweed//pw_interrupt_cortex_m:backend",
         "@pigweed//targets/stm32f429i_disc1_stm32cube:freertos_config_cv",
         "@pigweed//pw_sys_io_stm32cube:backend",
+        "@platforms//os:none",
 
         # For toolchain selection.
         "@platforms//cpu:armv7e-m",