diff --git a/libusb/core.c b/libusb/core.c
index a5ab057..010b3c0 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -2288,7 +2288,8 @@ void API_EXPORTED libusb_set_log_cb(libusb_context *ctx, libusb_log_cb cb,
  * on this platform
  * \returns \ref LIBUSB_ERROR_NOT_FOUND if LIBUSB_OPTION_USE_USBDK is valid on this platform but UsbDk is not available
  */
-int API_EXPORTEDV libusb_set_option(libusb_context *ctx,
+// NOTE: Removed API_EXPORTEDV since SysV ABI cannot be used with va_list.
+int /*API_EXPORTEDV*/ libusb_set_option(libusb_context *ctx,
 	enum libusb_option option, ...)
 {
 	int arg = 0, r = LIBUSB_SUCCESS;
diff --git a/libusb/libusb.h b/libusb/libusb.h
index efe3728..7f1f200 100644
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -2404,7 +2404,8 @@ void LIBUSB_CALL libusb_hotplug_deregister_callback(libusb_context *ctx,
 void * LIBUSB_CALL libusb_hotplug_get_user_data(libusb_context *ctx,
 	libusb_hotplug_callback_handle callback_handle);
 
-int LIBUSB_CALLV libusb_set_option(libusb_context *ctx, enum libusb_option option, ...);
+// NOTE: Removed LIBUSB_CALLV since SysV ABI cannot be used with va_list.
+int /*LIBUSB_CALLV*/ libusb_set_option(libusb_context *ctx, enum libusb_option option, ...);
 
 #ifdef _MSC_VER
 #pragma warning(pop)
diff --git a/libusb/os/windows_winusb.c b/libusb/os/windows_winusb.c
index c77bd20..dd000ec 100644
--- a/libusb/os/windows_winusb.c
+++ b/libusb/os/windows_winusb.c
@@ -3057,7 +3057,7 @@ static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_ha
 }
 
 
-static void WINAPI winusbx_native_iso_transfer_continue_stream_callback(struct libusb_transfer *transfer)
+static void LIBUSB_CALL winusbx_native_iso_transfer_continue_stream_callback(struct libusb_transfer *transfer)
 {
 	// If this callback is invoked, this means that we attempted to set ContinueStream
 	// to TRUE when calling Read/WriteIsochPipeAsap in winusbx_submit_iso_transfer().