Fix compilation issues with C++17

Testable on Linux/macOS by changing c++14 to c++1z in qtcreator.pri.
Testable with latest MSVC2017 by setting _CL_=/std:c++17.

unary_function, binary_function, and a few other things that were
deprecated are removed in C++17.
std::string got a non-const overload for its "data" member function,
so we cannot create a function pointer on it without specifying its
type. Use std::declval instead (though it requires a default constructor
for the type).

MSVC seems to have an issue with Utils::transform for std::vector
(used in Nim plugin), but that looks like a compiler issue.

Change-Id: I94f9a93d591d55b610f86fabfc618158927d6221
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/texteditor/behaviorsettingswidget.cpp

@@ -59,7 +59,7 @@ BehaviorSettingsWidget::BehaviorSettingsWidget(QWidget *parent)
     QList<int> mibs = QTextCodec::availableMibs();
     Utils::sort(mibs);
     QList<int>::iterator firstNonNegative =
-        std::find_if(mibs.begin(), mibs.end(), std::bind2nd(std::greater_equal<int>(), 0));
+        std::find_if(mibs.begin(), mibs.end(), [](int n) { return n >=0; });
     if (firstNonNegative != mibs.end())
         std::rotate(mibs.begin(), firstNonNegative, mibs.end());
     foreach (int mib, mibs) {