This reverts commit 615326be9b because it
breaks windows builds.
```
File "/home/ardour/ardour-w64/wscript", line 1462, in configure
set_compiler_flags (conf, Options.options)
File "/home/ardour/ardour-w64/wscript", line 522, in set_compiler_flags
if re.search ('x86_64-w64', conf.env['CC']) is not None:
File "/usr/lib/python2.7/re.py", line 146, in search
return _compile(pattern, flags).search(string)
TypeError: expected string or buffer
```