Wrong behaviour calling qmake on Windows with qt.conf

On Windows, with a qt.conf calling "qmake -query" give the expected behaviour while calling "qmake.exe -query" return the builtin paths.
I fixed this issue replacing code near line 350 of qmake/option.cpp:

#ifdef Q_OS_WIN
candidate += ".exe";
#else

WITH:

#ifdef Q_OS_WIN
if (!candidate.endsWith(".exe"))
candidate += ".exe";
#endif