Improve dbghelp.dll finding on ARM64 (winsiderss#790)

Author: Mattiwatti

phlib/symprv.c

@@ -275,8 +275,10 @@ VOID PhpSymbolProviderCompleteInitialization(
         PPH_STRING dbghelpName;
         PPH_STRING symsrvName;
 
-#ifdef _WIN64
+#if defined(_M_AMD64)
         PhMoveReference(&winsdkPath, PhConcatStringRefZ(&winsdkPath->sr, L"\\Debuggers\\x64\\"));
+#elif defined(_M_ARM64)
+        PhMoveReference(&winsdkPath, PhConcatStringRefZ(&winsdkPath->sr, L"\\Debuggers\\arm64\\"));
 #else
         PhMoveReference(&winsdkPath, PhConcatStringRefZ(&winsdkPath->sr, L"\\Debuggers\\x86\\"));
 #endif