desubmodulize libsndfile - PLEASE READ

it appears a one-character typo in the cmake_minimum_required line prevents it from compiling under CMake 4.0.
in order to fix that, I had to take this thing out of submodules...

it is recommended to do this after you pull;

git submodule deinit extern/libsndfile

extern/libsndfile-modified/.github/workflows/cifuzz.yml

@@ -0,0 +1,26 @@
+name: CIFuzz
+on: [pull_request]
+jobs:
+  Fuzzing:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Build Fuzzers
+      id: build
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'libsndfile'
+        dry-run: false
+        language: c
+    - name: Run Fuzzers
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'libsndfile'
+        fuzz-seconds: 600
+        dry-run: false
+        language: c
+    - name: Upload Crash
+      uses: actions/upload-artifact@v1
+      if: failure() && steps.build.outcome == 'success'
+      with:
+        name: artifacts
+        path: ./out/artifacts