New warnfixes (#2254)

* Fix clang warnings

* Remove vim tab guides

* initialize variables

* 'strncpy' output truncated before terminating nul copying as many bytes from a string as its length

* Fix ISO C++17 does not allow 'register' storage class specifier for outdated bison

* chars are unsigned on ARM, having  if (ival < 0) always false

* chars are unsigned by default on ARM and comparison with -1 if always true

utils/windowfunction/windowfunction.cpp

@@ -259,4 +259,3 @@ void WindowFunction::sort(std::vector<RowPosition>::iterator v, uint64_t n)
 }
 
 }  // namespace windowfunction
-// vim:ts=4 sw=4: