Utils: More explicit host os use to make it stand out

Quite a few of the uses are actually wrong, but are better visible
now and therefore more likely to be fixed.

Change-Id: Ia51f7d6eb1b2d3a9c9f73d67dabacfd227c44b15
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/genericprojectmanager/genericproject.cpp

@@ -400,7 +400,7 @@ static QStringList readFlags(const QString &filePath)
         return QStringList();
     QStringList flags;
     for (const auto &line : lines)
-        flags.append(ProcessArgs::splitArgs(line));
+        flags.append(ProcessArgs::splitArgs(line, HostOsInfo::hostOs()));
     return flags;
 }