windows/msvc: use high level processor feature detection API

see https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-isprocessorfeaturepresent

gpt4all-backend/llmodel.cpp

@@ -10,6 +10,9 @@
 #include <cassert>
 #include <cstdlib>
 #include <sstream>
+#ifdef _MSC_VER
+#include <processthreadsapi.h>
+#endif
 
 std::string s_implementations_search_path = ".";
 
@@ -18,9 +21,7 @@ static bool has_at_least_minimal_hardware() {
     #ifndef _MSC_VER
         return __builtin_cpu_supports("avx");
     #else
-        int cpuInfo[4];
+        return IsProcessorFeaturePresent(PF_AVX_INSTRUCTIONS_AVAILABLE);
-        __cpuid(cpuInfo, 1);
-        return cpuInfo[2] & (1 << 28);
     #endif
 #else
     return true; // Don't know how to handle non-x86_64
@@ -32,9 +33,7 @@ static bool requires_avxonly() {
     #ifndef _MSC_VER
         return !__builtin_cpu_supports("avx2");
     #else
-        int cpuInfo[4];
+        return !IsProcessorFeaturePresent(PF_AVX2_INSTRUCTIONS_AVAILABLE);
-        __cpuidex(cpuInfo, 7, 0);
-        return !(cpuInfo[1] & (1 << 5));
     #endif
 #else
     return false; // Don't know how to handle non-x86_64