b10917

cmake : skip PCH for llama-server PCH when using MSVC (#28763)

This commit fixes an issue that I introduced when adding PCH
(precompiled headers) in Commit 3bcfeb7
("cmake : add PCH and unity build to improve build times (#28091)".

See linked issue for details.

Co-authored-by: mjungnickel18
Co-authored-by: Pascal admin@serveurperso.com

Resolves: #28758
Refs: https://github.com/ggml-org/llama.cpp/actions/runs/34592933983/job/103262608990#step:9:1284

Website:

• https://llama.app

Attestations:

• https://github.com/ggml-org/llama.cpp/attestations/46958058

macOS/iOS:

• macOS Apple Silicon (arm64)
• macOS Apple Silicon (arm64, KleidiAI enabled) DISABLED
• macOS Intel (x64)
• iOS XCFramework

Linux:

• Ubuntu x64 (CPU)
• Ubuntu arm64 (CPU)
• Ubuntu s390x (CPU)
• Ubuntu x64 (Vulkan)
• Ubuntu arm64 (Vulkan)
• Ubuntu x64 (ROCm 10.0)
• Ubuntu x64 (OpenVINO)
• Ubuntu x64 (SYCL FP32)
• Ubuntu x64 (SYCL FP16)

Android:

• Android arm64 (CPU)

Windows:

• Windows x64 (CPU)
• Windows arm64 (CPU)
• Windows arm64 (OpenCL Adreno)
• Windows x64 (CUDA 12) - CUDA 12.4 DLLs
• Windows x64 (CUDA 13) - CUDA 13.3 DLLs
• Windows arm64 (CUDA 13) - CUDA 13.4 DLLs
• Windows x64 (Vulkan)
• Windows x64 (OpenVINO)
• Windows x64 (SYCL)
• Windows x64 (ROCm 10.0)

openEuler:

• DISABLED
• openEuler x86 (310p)
• openEuler x86 (910b, ACL Graph)
• openEuler aarch64 (310p)
• openEuler aarch64 (910b, ACL Graph)

UI:

• UI