low-memory *printf deadlocks with latest glibc in -testing and rawhide

[Jim Meyering]

So far I've only noticed it via a test, but everyone uses *printf,
and malloc is implicated due to recent arena-related changes:

    malloc deadlock makes *printf hang
    http://bugzilla.redhat.com/753601

With glibc-2.14.90-15.2.x86_64 (f16-testing and rawhide), this hangs:

    ( ulimit -v 10000; env printf %20000000f 0 )

Hah!  As I was writing this, I noticed a new glibc commit.

http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=a5fb313cb7b7e692fd4684916aaa98e03ec7e8b6

Thanks for the quick fix, Andreas!