#define within a #include file from interactive mode crashes about picoc HOT 2 OPEN

The problem occurs whenever a #include statement is entered in interactive 
mode. The crash occurs in LexCopyTokens at the line:

if (EndParser->Pos >= StartParser->Pos && EndParser->Pos < 
&pc->InteractiveCurrentLine->Tokens[pc->InteractiveCurrentLine->NumBytes])

because pc->InteractiveCurrentLine is null. The root of the problem appears to 
be that Picoc_struct has global lexer data, but when you're in immediate mode 
and you #include, you're re-entering the lexer.

I believe I've solved this.

In include.c, in void IncludeFile(Picoc *pc, char *FileName), replace:

   PicocPlatformScanFile(pc, FileName);

with code that saves the global values, sets them to NULL, then restores them 
afterwards:

    {
        struct TokenLine *head = pc->InteractiveHead, *tail = pc->InteractiveTail, *line = pc->InteractiveCurrentLine;
        pc->InteractiveHead = pc->InteractiveTail = pc->InteractiveCurrentLine = NULL;
        PicocPlatformScanFile(pc, FileName);
        pc->InteractiveHead = head;
        pc->InteractiveTail = tail;
        pc->InteractiveCurrentLine = line;
    }

This is fixed on my fork at https://github.com/galacticstudios/picoc