test_distutils should only dump stdout/stderr on compilation failure, but hide them on success (by default).

Example of output:

http://buildbot.python.org/all/builders/x86%20Windows7%203.x/builds/588/steps/test/logs/stdio

0:58:52 [277/405/1] test_distutils passed (124 sec) -- running: test_tokenize (322 sec)
xxmodule.c
   Creating library d:\temp\tmp1byjf67b\Debug\temp\tmp1byjf67b\xx_d.cp37-win32.lib and object d:\temp\tmp1byjf67b\Debug\temp\tmp1byjf67b\xx_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
foo.c
   Creating library d:\temp\tmp78_8qa47\tempt\temp\tmpduqip5h3\foo_d.cp37-win32.lib and object d:\temp\tmp78_8qa47\tempt\temp\tmpduqip5h3\foo_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
foo.c
   Creating library d:\temp\tmp78_8qa47\tempt\temp\tmpduqip5h3\foo_d.cp37-win32.lib and object d:\temp\tmp78_8qa47\tempt\temp\tmpduqip5h3\foo_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
xxmodule.c
   Creating library d:\temp\tmpruuda1qt\Debug\temp\tmpruuda1qt\xx_d.cp37-win32.lib and object d:\temp\tmpruuda1qt\Debug\temp\tmpruuda1qt\xx_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
foo.c
   Creating library d:\temp\tmpxzrh56h5\tempt\temp\tmpht642isv\foo_d.cp37-win32.lib and object d:\temp\tmpxzrh56h5\tempt\temp\tmpht642isv\foo_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
foo.c
   Creating library d:\temp\tmpxzrh56h5\tempt\temp\tmpht642isv\foo_d.cp37-win32.lib and object d:\temp\tmpxzrh56h5\tempt\temp\tmpht642isv\foo_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance
xxmodule.c
   Creating library build\temp.win32-3.7-pydebug\Debug\xx_d.cp37-win32.lib and object build\temp.win32-3.7-pydebug\Debug\xx_d.cp37-win32.exp
LINK : /LTCG specified but no code generation required; remove /LTCG from the link command line to improve linker performance

D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\build\test_python_204>exit 1 

D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\build\test_python_204>exit 0

The problem here I think is that distutils itself should only dump stdout/stderr on failure, but because of how it spawns processes it never actually captures the output from external tools.

We really need to update distutils's spawn() function to use subprocess. That would also resolve a handful of other issues.

> The problem here I think is that distutils itself should only dump stdout/stderr on failure, ...

Hum, I would like to see warnings even if the compilation succeed. So I would prefer to only modify test_distutils.