Extend python<->PLC global variable description "GlobalDesc" to support Initial value setting.
Rebased from dporopat change "add initial value to runtime.py file", which means :
- GlobalDesc is used by some customized beremiz python runtime
- Those runtimes need to know what is initial value of these special variables
/* Beremiz' header file for use by extensions */
#include "iec_types.h"
#define LOG_LEVELS 4
#define LOG_CRITICAL 0
#define LOG_WARNING 1
#define LOG_INFO 2
#define LOG_DEBUG 3
extern unsigned long long common_ticktime__;
int LogMessage(uint8_t level, char* buf, uint32_t size);
long AtomicCompareExchange(long* atomicvar,long compared, long exchange);