test-quotearg failure

[Eric Blake]

Cygwin 1.7 recently switched its default locale from C.ASCII over to C.UTF-8 
(valid UTF-8 sequences are handled as multibyte characters, and invalid UTF-8 
sequences are managed transparently rather than causing encoding errors, so 
that 8-bit data from another charset can be transparently handled in contexts 
where bytes rather than characters are needed.  Meanwhile, special mangling of 
invalid UTF-8 sequences is used to guarantee that any char string can make the 
round trip in and back out of valid UTF-16 wchar_t strings to all underlying 
Windows system calls).  It looks like Debian is in the process of doing 
something similar, of making the default C locale use a UTF-8 multibyte 
charset.  As a result, test-quotearg.sh now fails on cygwin 1.7, because the 
UTF-encoded multi-byte sequence "\302\253\302\273" is now recognized as two 
printable characters, rather than four unprintable bytes, and thus not being 
quoted in the same manner as it was in a unibyte ASCII locale.

I'm not exactly sure how to fix the test to deal with the fact that not all C 
locales are created equal when it comes to bytes with the 8th bit set.  But 
hopefully I figure out something soon.

-- 
Eric Blake