Utils: Modernize further

Many issues, mostly in headers, were not addressed in
e38410b76c

modernize-use-auto
modernize-use-nullptr
modernize-use-override
modernize-use-using
modernize-use-default-member-init
modernize-use-equals-default

Change-Id: I320a51726db881e582b898948d53735ebb06887a
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/qtcprocess.cpp

@@ -668,9 +668,7 @@ bool QtcProcess::prepareCommand(const QString &command, const QString &arguments
 }
 
 QtcProcess::QtcProcess(QObject *parent)
-    : QProcess(parent),
-      m_haveEnv(false),
-      m_useCtrlCStub(false)
+    : QProcess(parent)
 {
     static int qProcessExitStatusMeta = qRegisterMetaType<QProcess::ExitStatus>();
     static int qProcessProcessErrorMeta = qRegisterMetaType<QProcess::ProcessError>();