ggml: improve SPIR-V headers detection with __has_include (ggml-org#21918)

* ggml: improve SPIR-V headers detection with __has_include while preserving original _WIN32 logic

* Address review comments: fix fallback logic and add FreeBSD support

* Remove spirv_cross fallback as per review

* Remove redundant __has_include check

Author: EmilAskerov

ggml/src/ggml-vulkan/ggml-vulkan.cpp

@@ -20,12 +20,19 @@ DispatchLoaderDynamic & ggml_vk_default_dispatcher();
 #define VULKAN_HPP_DEFAULT_DISPATCHER ggml_vk_default_dispatcher()
 
 #include <vulkan/vulkan.hpp>
-// SPIRV-Headers: LunarG Windows SDK uses Include/spirv-headers/spirv.hpp (not spirv/unified1/). MinGW/MSYS2 and
-// Linux packages use Khronos layout spirv/unified1/spirv.hpp. See docs/build.md#vulkan.
-#if defined(_WIN32) && !defined(__MINGW32__)
-#include <spirv-headers/spirv.hpp>
+
+// SPIR-V Headers: different SDK installations expose different include paths.
+// LunarG Vulkan SDK on Windows typically provides <spirv-headers/spirv.hpp>.
+// Linux packages, MSYS2 and MinGW often use the Khronos layout <spirv/unified1/spirv.hpp>.
+#if __has_include(<spirv/unified1/spirv.hpp>)
+#    include <spirv/unified1/spirv.hpp>
+#elif __has_include(<spirv-headers/spirv.hpp>)
+#    include <spirv-headers/spirv.hpp>
+#elif __has_include(<spirv.hpp>)
+#    include <spirv.hpp>
 #else
-#include <spirv/unified1/spirv.hpp>
+     // Fallback to let the compiler throw a standard "file not found" error
+#    include <spirv/unified1/spirv.hpp>
 #endif
 
 #include <algorithm>