chunihook: Explicitly load dbghelp.dll so path hooks apply to it

- This allows AMLib (in Chunithm and other games) to successfully
  initialize without requiring the game to be run as Administrator on
  first boot to create `C:\Users\AppUser\temp`.

chunihook/dllmain.c

@@ -30,6 +30,7 @@ static struct chuni_hook_config chuni_hook_cfg;
 static DWORD CALLBACK chuni_pre_startup(void)
 {
     HMODULE d3dc;
+    HMODULE dbghelp;
     HRESULT hr;
 
     dprintf("--- Begin chuni_pre_startup ---\n");
@@ -44,6 +45,16 @@ static DWORD CALLBACK chuni_pre_startup(void)
         dprintf("Failed to load shader compiler!\n");
     }
 
+    /* Pin dbghelp so the path hooks apply to it. */
+
+    dbghelp = LoadLibraryW(L"dbghelp.dll");
+
+    if (dbghelp != NULL) {
+        dprintf("Pinned debug helper library, hMod=%p\n", dbghelp);
+    } else {
+        dprintf("Failed to load debug helper library!\n");
+    }
+
     /* Config load */
 
     chuni_hook_config_load(&chuni_hook_cfg, L".\\segatools.ini");