Utils: Only write data to process if there is any

This avoids the warning
QIODevice::write (QProcess): ReadOnly device
in cases where the process is run inside a read only
directory even when the process has no input.

Change-Id: I9434c738e9cf94c348f1437ebf15e1c7574cde94
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/synchronousprocess.cpp

@@ -481,10 +481,12 @@ SynchronousProcessResponse SynchronousProcess::run(const CommandLine &cmd,
     // only with the OpenMode
     d->m_process.setProgram(cmd.executable().toString());
     d->m_process.setArguments(cmd.splitArguments());
+    if (!writeData.isEmpty()) {
         connect(&d->m_process, &QProcess::started, this, [this, writeData] {
             d->m_process.write(writeData);
             d->m_process.closeWriteChannel();
         });
+    }
     d->m_process.start(writeData.isEmpty() ? QIODevice::ReadOnly : QIODevice::ReadWrite);
 
     // On Windows, start failure is triggered immediately if the