[Bug libstdc++/86553] libstdc++-v3 build failure on AIX 5.3

[bugzilla-gcc at thewrittenword dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86553

--- Comment #2 from The Written Word <bugzilla-gcc at thewrittenword dot com> 
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gcc-6.4.0 on AIX 5.3 exhibits a similar failure.