bdist_wininst command ignores --plat-name option for executable launcher

Originally reported by: jun66j5 (Bitbucket: jun66j5, GitHub: jun66j5)

I created Windows installers for win32 and win-amd64 platforms using bdist_wininst command.

C:> python.exe setup.py clean -a build --plat-name=win32 bdist_wininst --plat-name=win32
...
C:> python.exe setup.py clean -a build --plat-name=win-amd64 bdist_wininst --plat-name=win-amd64
...

However, it seems that the both win32 and win-amd64 installers use cli-32.exe for executable launchers. I think win-amd64 installer should use cli-64.exe launcher.

C:> unzip -l dist\Trac-1.0.2beta1-r13120.win-amd64.exe | grep -F .exe
warning [dist/Trac-1.0.2beta1-r13120.win-amd64.exe]:  264579 extra bytes at beginning or within zipfile
  (attempting to process anyway)
Archive:  dist/Trac-1.0.2beta1-r13120.win-amd64.exe
    65536      0      0  14-09-08 16:46   SCRIPTS/trac-admin.exe
      645      0      0  14-09-08 16:46   SCRIPTS/trac-admin.exe.manifest
    65536      0      0  14-09-08 16:46   SCRIPTS/tracd.exe
      640      0      0  14-09-08 16:46   SCRIPTS/tracd.exe.manifest

C:> unzip -l dist\Trac-1.0.2beta1-r13120.win32.exe | grep -F .exe
warning [dist/Trac-1.0.2beta1-r13120.win32.exe]:  236931 extra bytes at beginning or within zipfile
  (attempting to process anyway)
Archive:  dist/Trac-1.0.2beta1-r13120.win32.exe
    65536      0      0  14-09-08 16:33   SCRIPTS/trac-admin.exe
      645      0      0  14-09-08 16:33   SCRIPTS/trac-admin.exe.manifest
    65536      0      0  14-09-08 16:33   SCRIPTS/tracd.exe
      640      0      0  14-09-08 16:33   SCRIPTS/tracd.exe.manifest

C:> dir Lib\site-packages\setuptools\cli-*.exe
...
2014-08-22  02:34            65,536 cli-32.exe
2014-08-22  02:34            74,752 cli-64.exe
2014-08-22  02:34            69,120 cli-arm-32.exe

• Bitbucket: https://bitbucket.org/pypa/setuptools/issue/253

Start with the bdist_wininst command and the setup.py invocation shown in the report, then inspect how the executable launcher is selected for --plat-name=win32 and --plat-name=win-amd64. Compare the generated installers and the listed cli-32.exe and cli-64.exe files; done means the win-amd64 installer includes cli-64.exe while win32 continues to include cli-32.exe.