fixed some compilation errors when compiling using clang-cl.exe

[georg-emg]

When compiling the osal sub directory under Windows using clang-cl.exe, some compiler errors occurred. This patch fixes these errors, so that SOEM can be built under Windows using clang-cl.

[nakarlsson]

The declaration of osal_gettimeofday can be removed hence no need to add forward declaration of struct timezone.
I believe osal_win32.h might be removed all together

[nakarlsson]

I'd prefer to typecast it to PHANDLE instead of void ** , very much like the linux port

int osal_thread_create(void *thandle, int stacksize, void *func, void *param)
{
PHANDLE phandle = thandle;

*phandle = CreateThread(NULL, stacksize, func, param, 0, NULL);
if(*phandle != NULL)
{
return 0;
}
return 1;
}

int osal_thread_create_rt(void *thandle, int stacksize, void *func, void *param)
{
int ret;
PHANDLE phandle = thandle;

ret = osal_thread_create(phandle, stacksize, func, param);
if (ret)
{
ret = SetThreadPriority(*phandle, THREAD_PRIORITY_TIME_CRITICAL);
}
return ret;
}

[nakarlsson]

@georg-emg , sorry for late response. Small suggestions and I don't have clang on windows so please test and give feedback.

[aditmak]

@nakarlsson, suggested changes have been added and tested with clang.