fix(nemo-speech-cpp): support CMake 4

Homebrew CMake 4 rejects the pinned SentencePiece project because it requests compatibility below version 3.5. Pass the supported policy floor when Darwin runs the upstream helper.

Assisted-by: Codex:gpt-5.6 [Codex]

Author: localai-org-maint-bot

backend/go/nemo-speech-cpp/Makefile

@@ -284,7 +284,10 @@ $(SENTENCEPIECE_MARKER): | sources/NeMo-Speech.cpp
 	# four license installs otherwise unchanged.
 ifeq ($(shell uname -s),Darwin)
 	mkdir -p $(SENTENCEPIECE_PREFIX)/share/licenses/nemo-speech/third_party/sentencepiece
-	sed -i.bak 's/install -Dm0644/install -m 0644/' sources/NeMo-Speech.cpp/scripts/build_sentencepiece_static.sh
+	sed -i.bak \
+		-e 's/install -Dm0644/install -m 0644/' \
+		-e 's/-DCMAKE_BUILD_TYPE=Release \\/-DCMAKE_BUILD_TYPE=Release -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \\/' \
+		sources/NeMo-Speech.cpp/scripts/build_sentencepiece_static.sh
 endif
 	cd sources/NeMo-Speech.cpp && JOBS=$(JOBS) scripts/build_sentencepiece_static.sh