[Bug bootstrap/54419] [4.8 Regression] Compiling libstdc++-v3/src/c++11/random.cc fails on platforms not knowing rdrand

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54419

--- Comment #21 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-09-04 10:27:58 UTC ---
> How about this patch?  Not sure whether this handles cross-compiling.  It seems
> to work for me.

Before I test the patch, I am surprised to see that only two out of three
blocks

#if defined __i386__ || defined __x86_64__

are "protected" by  && defined _GLIBCXX_X86_RDRAND. Is it normal?

> I still think it's wrong to bother with obsolete assemblers...

Well, users have to deal with the tool chain they can get (I'ld be delighted to
have a working modern gas on darwin, but so far no one is providing it).