Build fails on Linux (GCC 15): SentencePiece missing <cstdint> + Highway avx10.2-512 errors

# Summary

Building gemma.cpp on Linux with GCC 15 fails due to issues in third-party dependencies:
1. CMake fails version check
2. sentencepiece headers fail to compile due to missing include

# Environment

* OS: Arch Linux
* cmake: 4.1.2
* clang: 21.1.6
* gcc: 15.2.1
* gemma.cpp: latest main (Nov 2025)

# Workaround Build steps

### 1) Specify clang and cmake version compatibility

`CC=clang CXX=clang++ cmake --preset make -DCMAKE_POLICY_VERSION_MINIMUM=3.5`

### 2) Add missing include in sentencepiece

`sed -i '24i #include ' build/_deps/sentencepiece-src/src/sentencepiece_processor.h`

### 3) Build

`cmake --build --preset make -j$(nproc)`