Fix up std:: namespace hygiene.

* Remove all uses of `using namespace std` from header files (although a
  few specific cases of things like `using std::vector` remain)
* Move all existing uses of `using namespace std` in cpp files to after the
  header includes
* Make coordinating changes so it builds again.

Qt6 builds on Windows were breaking because of namespace collision between
std::byte and some version of `byte` in one of Qt's namespaces.  That breakage
is now fixed.

It would be good to systematically clean up all `using` declarations in header
files to ensure nothing is leaking out, but that's for another time.

1 files changed, 2 insertions, 0 deletions

diff --git a/quacker/newgame.cpp b/quacker/newgame.cpp
index 001d37d..4d5c5a2 100644
--- a/quacker/newgame.cpp
+++ b/quacker/newgame.cpp
@@ -27,6 +27,8 @@
 #include "newgame.h"
 #include "customqsettings.h"
 
+using namespace std;
+
 NewGameDialog::NewGameDialog(QWidget *parent)
 	: QDialog(parent)
 {