In a header file of your C/C++ application or extension
that includes the Tcl library, add these lines

  #include <tcl.h>
  ...
  #if (TCL_MAJOR_VERSION < 8) || (TCL_MAJOR_VERSION == 8) && (TCL_MINOR_VERSION < 6)
  #define Tcl_GetErrorLine(interp) (interp->errorLine)
  #endif

Why?  This helps you deprecate direct access to interp->errorLine
so you can upgrade your code written for pre-8.6 Tcl so it can be
used with Tcl 8.6, yet still work with earlier Tcl releases.

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[LV] It seems, to me, that tidbits like these would be really useful to collect somewhere to ensure that developers or maintainers don't overlook them. I'm not certain, however, of the best way to do this.

[Changes to consider when moving to Tcl 8.6[

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!!!!!!
%| [Category Porting] |%
!!!!!!