fix(nemo-speech-cpp): build required sentencepiece

The updated runtime uses SentencePiece for RNNT context biasing even when Flashlight and text normalization are disabled. Build upstream's pinned static archive before configuring the engine so every backend variant has the newly required library and headers.

Assisted-by: Codex:gpt-5

Author: localai-org-maint-bot

backend/go/nemo-speech-cpp/Makefile

@@ -88,6 +88,18 @@ ITN_LIB_DIR=$(ITN_PREFIX)/lib
 ITN_MARKER=$(ITN_LIB_DIR)/libsparrowhawk.so
 ITN_FST_HEADER=$(ITN_PREFIX)/include/fst/fst.h
 
+# SentencePiece became a core ASR dependency in 5be7bfb: RNNT context biasing
+# uses it even when Flashlight and text normalization are disabled. Build the
+# pinned static archive provided by upstream so every platform gets the same
+# dependency instead of relying on an undeclared system package.
+SENTENCEPIECE_PREFIX=sources/NeMo-Speech.cpp/.deps/sentencepiece
+SENTENCEPIECE_MARKER=$(SENTENCEPIECE_PREFIX)/lib/libsentencepiece.a
+
+# Linux's ASR CMake block looks in NEMO_SPEECH_DEPENDENCY_PREFIX directly, but
+# the Apple branch uses generic find_library()/find_path(). Put the same private
+# prefix on CMake's search path so Darwin consumes the archive built above too.
+CMAKE_ARGS+=-DCMAKE_PREFIX_PATH=$(abspath $(SENTENCEPIECE_PREFIX))
+
 ITN_CC?=gcc-12
 ITN_CXX?=g++-12
 
@@ -152,7 +164,7 @@ else
 endif
 CMAKE_ARGS+=-DNEMO_SPEECH_GGML_PATCHED=$(GGML_PATCHED)
 
-.PHONY: nemo-speech-cpp-grpc package build clean purge test all stage-libs patch-ggml engine itn patch-itn-headers
+.PHONY: nemo-speech-cpp-grpc package build clean purge test all stage-libs patch-ggml engine itn sentencepiece patch-itn-headers
 
 all: nemo-speech-cpp-grpc package
 
@@ -266,11 +278,17 @@ patch-itn-headers:
 
 itn: $(ITN_MARKER)
 
+$(SENTENCEPIECE_MARKER): | sources/NeMo-Speech.cpp
+	cd sources/NeMo-Speech.cpp && JOBS=$(JOBS) scripts/build_sentencepiece_static.sh
+
+sentencepiece: $(SENTENCEPIECE_MARKER)
+
 # Only a WITH_NORM=ON build needs the ITN stack, and it must exist before cmake
 # configures, since the WITH_NORM cmake block find_library()s into the prefix
 # with REQUIRED.
+NEMO_RUNTIME_PREREQS=$(SENTENCEPIECE_MARKER)
 ifeq ($(WITH_NORM),ON)
-NEMO_RUNTIME_PREREQS=$(ITN_MARKER)
+NEMO_RUNTIME_PREREQS+=$(ITN_MARKER)
 endif
 
 # Upstream sets CMAKE_LIBRARY_OUTPUT_DIRECTORY to ${CMAKE_BINARY_DIR}/bin, so the