fix many compilation warnings about static variables used by non-static functions

[CC] plc_main.c -> plc_main.o
/tmp/be/build/plc_main.c:396:40: warning: ?LogBuff? is static but used in inline function ?copy_from_log? which is not static
memcpy((char*)buf + remaining, LogBuff[level], size - remaining);
^
/tmp/be/build/plc_main.c:395:22: warning: ?LogBuff? is static but used in inline function ?copy_from_log? which is not static
memcpy(buf, &LogBuff[level][buffpos], remaining);
^
...

^
/tmp/be/build/plc_debugger.c:825:20: warning: ?retain_offset? is static but used in inline function ?BufferIterator? which is not static
Retain(retain_offset, size, real_value_p);
^
/tmp/be/build/plc_debugger.c:823:47: warning: ?retain_offset? is static but used in inline function ?BufferIterator? which is not static
unsigned int next_retain_offset = retain_offset + size;
^
^

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from editors.TextViewer import TextViewer

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from plcopen.plcopen import TestTextElement

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class IECCodeViewer(TextViewer):

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    def __del__(self):

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        TextViewer.__del__(self)

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        if getattr(self, "_OnClose"):

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            self._OnClose(self)

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    def Paste(self):

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        if self.Controler is not None:

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            TextViewer.Paste(self)

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    def Search(self, criteria):

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        return [((self.TagName, "body", 0),) + result for result in TestTextElement(self.Editor.GetText(), criteria)]