Draft: Fix C++ library missing all function symbols (#1063707)
0003-extern_C.patch was removed in 5.4.6-1 per request in #1032533, replacing all the C symbols with C++ mangled names, but the export map debian/version-script listed only C symbols.
Also fix identation of luaL_typeerror in debian/version-script and extend DEP-8 test to check C++ library.
Edited by P. J. McDermott