Add Wi-Fi OTA partition migration support

scripts/nrf52_lto_toolchain.py

@@ -0,0 +1,41 @@
+Import("env")
+
+# This script is loaded as a ``pre:`` extra script.  The Nordic platform's
+# builder selects binutils ar/ranlib later while it creates the library build
+# actions.  Those tools do not generate the plugin index required by GNU LTO,
+# which leaves the final link with hundreds of false "undefined reference"
+# errors.  Intercept that later replacement so every nRF52 archive is built
+# with GCC's plugin-aware wrappers.
+_replace = env.Replace
+
+
+def _replace_with_lto_archivers(*args, **kwargs):
+    if kwargs.get("AR") == "arm-none-eabi-ar":
+        kwargs["AR"] = "arm-none-eabi-gcc-ar"
+    if kwargs.get("RANLIB") == "arm-none-eabi-ranlib":
+        kwargs["RANLIB"] = "arm-none-eabi-gcc-ranlib"
+    return _replace(*args, **kwargs)
+
+
+env.Replace = _replace_with_lto_archivers
+
+# GCC runs the final whole-program passes while linking.  PlatformIO supplies
+# the project flags to compilation only, so forward the size policy explicitly
+# to that final LTO invocation as well.  One partition also avoids GCC 14
+# generating out-of-range Thumb literal loads in large nRF52 images.
+env.Append(LINKFLAGS=[
+    "-Oz",
+    "-flto",
+    "-flto-partition=one",
+    "-fno-inline-small-functions",
+    "-fipa-pta",
+    "-fmerge-all-constants",
+    "-fno-ipa-cp-clone",
+    "-fno-partial-inlining",
+    "-fno-jump-tables",
+    "-fno-tree-switch-conversion",
+    "-fno-semantic-interposition",
+    "-fno-unwind-tables",
+    "-fno-asynchronous-unwind-tables",
+    "-fno-schedule-insns2",
+])