QProcess::start removes some quotes in wrong way

Let's consider the following example.

Source code for a.cmd is:

@echo off
echo allargs=%*
echo arg1=%1
echo arg2=%2
echo arg3=%3
echo arg4=%4
echo arg5=%5
echo well done

Let's start that program with following command line from windows command prompt

a.cmd "" "alfa=a,b,c"

Please note 2 important things:

1. First arg is emtpy (that is what we want to be)
2. Second arg is quoted, because we want to be interpreted as single entity.

The output of described start is good and is what we want [O1]:

allargs="" "alfa=a,b,c"
arg1=""
arg2="alfa=a,b,c"
arg3=
arg4=
arg5=
well done

Now let's decide to use Qt to start our program:

  QProcess *process = new QProcess();
  QString cmd = "a.cmd \"\" \"alfa=a,b,c\"";
  process->start( cmd );

After Qt's start, we get new output [O2]:

allargs=alfa=a,b,c
arg1=alfa
arg2=a
arg3=b
arg4=c
arg5=
well done

This output [O2] is totally different from the desired output [O1].

Let's check what Qt did actually started (via Process Explorer from Sysinternals). It shows us the next command line:

C:\Windows\system32\cmd.exe /c a.cmd  alfa=a,b,c

It seems Qt somehow ruined our original command line. The documentation says that QProcess::start somehow
unquotes arguments and packs them back. Ok, this is not the problem.

But as we see, after Qt's unquotation/conversion of command line, the command line contains 2 problems.

PROBLEM 1. The first emtpy argument ("") is thrown away.
That is wrong behavior! We need 1st argument to be empty!

PROBLEM 2. The second argument ("alfa=a,b,c") lacks quotes!
That is wrong behavior! In windows, symbols "=" and "," are threatened as argument delimiters.
That's why our script shows 4 different args insteat of just one.

We think that in case we want to really pass alfa=a,b,c without quotes so cmd.exe will consider them as arguments delimiters, we will pass them to `QProcess::start` without quotes. But current `QProcess::start` implementation is not the case: it always removes our quotes!

Please consider Microsoft documentation on cmd.exe:

The following special characters require quotation marks: & < > [ ] { } ^ = ; ! ' + , ` ~ [white space]

from here https://technet.microsoft.com/en-us/library/bb490880.aspx

so, PROBLEM 2 is cmd-related, because cmd.exe requires quotation marks on symbols stated above.

Please, consider our report and fix QProcess::start appropriately.

Thank you very much!