diff --git a/steam_helper/steam.cpp b/steam_helper/steam.cpp
index 8ab65875..38712c62 100644
--- a/steam_helper/steam.cpp
+++ b/steam_helper/steam.cpp
@@ -654,7 +654,7 @@ static void parse_extensions(const char *in, uint32_t *out_count,
 
 extern "C"
 {
-    VkPhysicalDevice WINAPI __wine_get_native_VkPhysicalDevice(VkPhysicalDevice phys_dev);
+    VkPhysicalDevice __wine_get_native_VkPhysicalDevice(VkPhysicalDevice phys_dev);
 };
 
 static void *get_winevulkan_unix_lib_handle(HMODULE hvulkan)
diff --git a/vrclient_x64/unix_private.h b/vrclient_x64/unix_private.h
index 7b4d8e80..d1324180 100644
--- a/vrclient_x64/unix_private.h
+++ b/vrclient_x64/unix_private.h
@@ -16,11 +16,11 @@
 extern "C" {
 #endif /* __cplusplus */
 
-extern VkDevice_T *(WINAPI *p_get_native_VkDevice)( VkDevice_T * );
-extern VkInstance_T *(WINAPI *p_get_native_VkInstance)( VkInstance_T * );
-extern VkPhysicalDevice_T *(WINAPI *p_get_native_VkPhysicalDevice)( VkPhysicalDevice_T * );
-extern VkPhysicalDevice_T *(WINAPI *p_get_wrapped_VkPhysicalDevice)( VkInstance_T *, VkPhysicalDevice_T * );
-extern VkQueue_T *(WINAPI *p_get_native_VkQueue)( VkQueue_T * );
+extern VkDevice_T *(*p_get_native_VkDevice)( VkDevice_T * );
+extern VkInstance_T *(*p_get_native_VkInstance)( VkInstance_T * );
+extern VkPhysicalDevice_T *(*p_get_native_VkPhysicalDevice)( VkPhysicalDevice_T * );
+extern VkPhysicalDevice_T *(*p_get_wrapped_VkPhysicalDevice)( VkInstance_T *, VkPhysicalDevice_T * );
+extern VkQueue_T *(*p_get_native_VkQueue)( VkQueue_T * );
 
 extern char *json_convert_startup_info(const char *startup_info);
 extern char *json_convert_paths(const char *input);
diff --git a/vrclient_x64/unixlib.cpp b/vrclient_x64/unixlib.cpp
index ae477737..41e6d203 100644
--- a/vrclient_x64/unixlib.cpp
+++ b/vrclient_x64/unixlib.cpp
@@ -12,11 +12,11 @@ WINE_DEFAULT_DEBUG_CHANNEL(vrclient);
 static void *(*p_HmdSystemFactory)( const char *name, int *return_code );
 static void *(*p_VRClientCoreFactory)( const char *name, int *return_code );
 
-VkDevice_T *(WINAPI *p_get_native_VkDevice)( VkDevice_T * );
-VkInstance_T *(WINAPI *p_get_native_VkInstance)( VkInstance_T * );
-VkPhysicalDevice_T *(WINAPI *p_get_native_VkPhysicalDevice)( VkPhysicalDevice_T * );
-VkPhysicalDevice_T *(WINAPI *p_get_wrapped_VkPhysicalDevice)( VkInstance_T *, VkPhysicalDevice_T * );
-VkQueue_T *(WINAPI *p_get_native_VkQueue)( VkQueue_T * );
+VkDevice_T *(*p_get_native_VkDevice)( VkDevice_T * );
+VkInstance_T *(*p_get_native_VkInstance)( VkInstance_T * );
+VkPhysicalDevice_T *(*p_get_native_VkPhysicalDevice)( VkPhysicalDevice_T * );
+VkPhysicalDevice_T *(*p_get_wrapped_VkPhysicalDevice)( VkInstance_T *, VkPhysicalDevice_T * );
+VkQueue_T *(*p_get_native_VkQueue)( VkQueue_T * );
 
 static void *get_winevulkan_unixlib( HMODULE winevulkan )
 {
diff --git a/wineopenxr/openxr.c b/wineopenxr/openxr.c
index 0a4b9c18..d7c8d099 100644
--- a/wineopenxr/openxr.c
+++ b/wineopenxr/openxr.c
@@ -83,11 +83,11 @@ static char *wineopenxr_strdup(const char *src)
     return r;
 }
 
-VkDevice(WINAPI *get_native_VkDevice)(VkDevice);
-VkInstance(WINAPI *get_native_VkInstance)(VkInstance);
-VkPhysicalDevice(WINAPI *get_native_VkPhysicalDevice)(VkPhysicalDevice);
-VkPhysicalDevice(WINAPI *get_wrapped_VkPhysicalDevice)(VkInstance, VkPhysicalDevice);
-VkQueue(WINAPI *get_native_VkQueue)(VkQueue);
+VkDevice(*get_native_VkDevice)(VkDevice);
+VkInstance(*get_native_VkInstance)(VkInstance);
+VkPhysicalDevice(*get_native_VkPhysicalDevice)(VkPhysicalDevice);
+VkPhysicalDevice(*get_wrapped_VkPhysicalDevice)(VkInstance, VkPhysicalDevice);
+VkQueue(*get_native_VkQueue)(VkQueue);
 VkResult (WINAPI *p_wine_vkCreateInstance)(const VkInstanceCreateInfo *create_info,
         const VkAllocationCallbacks *allocator, VkInstance *ret);
 VkResult (WINAPI *p_wine_vkCreateDevice)(VkPhysicalDevice phys_dev, const VkDeviceCreateInfo *create_info,
diff --git a/wineopenxr/openxr_private.h b/wineopenxr/openxr_private.h
index f7e41f2d..c9e50243 100644
--- a/wineopenxr/openxr_private.h
+++ b/wineopenxr/openxr_private.h
@@ -122,9 +122,9 @@ extern XrResult WINAPI wine_xrGetD3D11GraphicsRequirementsKHR(XrInstance instanc
 extern XrResult WINAPI wine_xrGetD3D12GraphicsRequirementsKHR(XrInstance instance,
         XrSystemId systemId, XrGraphicsRequirementsD3D12KHR *graphicsRequirements);
 
-extern VkDevice (WINAPI *get_native_VkDevice)(VkDevice);
-extern VkInstance (WINAPI *get_native_VkInstance)(VkInstance);
-extern VkPhysicalDevice (WINAPI *get_native_VkPhysicalDevice)(VkPhysicalDevice);
-extern VkPhysicalDevice (WINAPI *get_wrapped_VkPhysicalDevice)(VkInstance, VkPhysicalDevice);
-extern VkQueue (WINAPI *get_native_VkQueue)(VkQueue);
+extern VkDevice (*get_native_VkDevice)(VkDevice);
+extern VkInstance (*get_native_VkInstance)(VkInstance);
+extern VkPhysicalDevice (*get_native_VkPhysicalDevice)(VkPhysicalDevice);
+extern VkPhysicalDevice (*get_wrapped_VkPhysicalDevice)(VkInstance, VkPhysicalDevice);
+extern VkQueue (*get_native_VkQueue)(VkQueue);
 extern XrResult load_host_openxr_loader(void);