uClibc support patch

[Joseph S. Myers]

I've identified bugs 14939, 20353, 24578, 24837 as relevant to this patch, 
have added notes to those PRs and will include those numbers in the log if 
the patch is approved.  The first three should be completely fixed by this 
patch, the fourth relates to the target-specific changes needed.

-- 
Joseph S. Myers               http://www.srcf.ucam.org/~jsm28/gcc/
    jsm@polyomino.org.uk (personal mail)
    joseph@codesourcery.com (CodeSourcery mail)
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