Migrated from Make to CMake.

third_party/README.md

@@ -29,3 +29,24 @@ vendored headers. The inspected JUCE 9.0.4 revision is AGPLv3/commercial; a
 commercial licence may be required. Original example source does not relicense
 JUCE or its dependencies. JUCE-linked outputs stay outside normal install and
 package targets. See [JUCE dependency/license details](../docs/JUCE.md).
+
+## CMake integration
+
+The root CMake target `xtc-core` uses the pinned CLAP/VST3 directories as private
+system include paths. No download step or SDK runtime is required. Configure
+optional full SDK builds explicitly:
+
+```sh
+cmake -S . -B build -DCMAKE_BUILD_TYPE=Release \
+  -DXTC_BUILD_STEINBERG=ON -DXTC_VST3_SDK_ROOT=/path/to/vst3sdk \
+  -DXTC_BUILD_JUCE=ON -DXTC_JUCE_ROOT=/path/to/JUCE
+cmake --build build --parallel 3
+ctest --test-dir build --output-on-failure -R 'steinberg|juce'
+```
+
+Leave both options off for normal builds. ASIO's native Windows diagnostic
+retains its separate CMake configuration described in the Steinberg examples;
+the Linux core is not a Windows/ASIO backend. See [BUILD.md](../docs/BUILD.md)
+for target options and [RELEASING.md](../docs/RELEASING.md) for staging. The
+owned install inventory retains the CLAP and VST3 C-header license notices;
+JUCE/official SDK plugin binaries are excluded from normal install/package targets.