cppcheck fix --HEAD

Recommended release build SRCDIR=build CFGDIR=cfg

Test before:
```
$ echo -n "" > main.cpp
$ cppcheck main.cpp
Failed to load std.cfg.
Your Cppcheck installation is broken, please re-install.
The Cppcheck binary was compiled without CFGDIR set.
Either the std.cfg should be available in cfg or the CFGDIR should be configured.
```