add getCompiler and getLinker methods, to abstract from XSD.
add calc_source_md5 as it's more convenient especially for embedded
targets to add -DPLC_MD5="something" option at compile time than
to mess with editing binary.
add some more helper methods

int CheckRetainBuffer(void)
{
	return 1;
}

void ValidateRetainBuffer(void)
{
}

void InValidateRetainBuffer(void)
{
}

void Retain(unsigned int offset, unsigned int count, void *p)
{
}

void Remind(unsigned int offset, unsigned int count, void *p)
{
}