Put extern "C" guards around all stub table struct definitions, so it is usable for C++ compilers as well without the danger of modifying the calling convention. 
For tclDecls.h it was no problem, because tcl.h already contains those guards. But for the other *Decls.h files (e.g. tclTomMathDecls.h) it was not correct.
Put extern "C" guards around all stub table struct definitions, so it is usable for C++ compilers as well without the danger of modifying the calling convention. 
For tclDecls.h and tclOODecls.h it was no problem, because tcl.h and tclOO.h already contain those guards. But for the other *Decls.h files (e.g. tclTomMathDecls.h) it was not correct.