Port from qAsConst() to std::as_const()

We've been requiring C++17 since Qt 6.0, and our qAsConst use finally
starts to bother us (QTBUG-99313), so time to port away from it
now.

Since qAsConst has exactly the same semantics as std::as_const (down
to rvalue treatment, constexpr'ness and noexcept'ness), there's really
nothing more to it than a global search-and-replace.

Task-number: QTBUG-99313
Change-Id: I88edd91395849574436299b8badda21bb93bea39
Reviewed-by: hjk <hjk@qt.io>

src/plugins/autotoolsprojectmanager/makefileparser.cpp

@@ -239,7 +239,7 @@ void MakefileParser::parseSubDirs()
 
     // Delegate the parsing of all sub directories to a local
     // makefile parser and merge the results
-    for (const QString &subDir : qAsConst(subDirs)) {
+    for (const QString &subDir : std::as_const(subDirs)) {
         const QChar slash = QLatin1Char('/');
         const QString subDirMakefile = path + slash + subDir
                                        + slash + makefileName;