Failed Crypto++ ppc64-le build dues to LLVM issue

[Jeffrey Walton]

Hi Everyone,

I help maintain the Crypto++ library. My testing on Debian with Clang
on ppc64-le results in failure.

I believe Clang needs this patch for ppc64-le:
https://bugs.llvm.org/show_bug.cgi?id=39704.

Thanks in advance.