## Issue

We got the following error when we built Groonga with MariaDB.

```
/home/buildbot/_deps/llama_cpp-src/ggml/src/ggml-cpu/ggml-cpu.c:3567:24: error: passing argument 1 of 'putenv' discards 'const' qualifier from pointer target type [-Werro =discarded-qualifiers]
```

## Cause

When building Groonga with MariaDB, the bundled llama.cpp triggers `-Werror`.

## Solution

Upstream llama.cpp doesn't setup discarded-qualifiers,
so we suppress the warning by explicitly passing `-Wno-discarded-qualifiers` in Debug and RelWithDebInfo builds.

```
rm -rf ../llama.cpp.build && \
cmake \
  -S . \
  -B ../llama.cpp.build \
  --preset=x64-linux-gcc-debug \
  -DCMAKE_C_COMPILER=clang \
  -DCMAKE_CXX_COMPILER=clang++ \
  -DCMAKE_INSTALL_PREFIX=/tmp/local \
  -DCMAKE_C_FLAGS="-Wwrite-strings -Werror=incompatible-pointer-types-discards-qualifiers" && \
cmake --build ../llama.cpp.build/
...
/home/otegami/work/cpp/llama.cpp/ggml/src/ggml-cpu/ggml-cpu.c:3572:24: error: passing 'const char[18]' to parameter of type 'char *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
 3572 |                 putenv("KMP_BLOCKTIME=200"); // 200ms
      |                        ^~~~~~~~~~~~~~~~~~~
```