[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 #15 from The Written Word <bugzilla-gcc at thewrittenword dot com> ---
Created attachment 44443
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44443&action=edit
gcc/config/rs6000/aix53.h patch

Similar to r227907 but for AIX 5.3 Have used this to successfully build
gcc-8.1.0 on AIX 5.3.