[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 #3 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-08-30 20:37:59 UTC ---
> The instruction is generated by the compiler.  If you try to compile a new
> compiler you have to make sure the tools used are recent enough to understand
> the output of the compiler.

Well, I think the compiler should check that the tools (or the CPU) support the
output it emits. Isn't it the purpose of the configure stages?

Concerning pre darwin12, there very little thing the user can do about which
instructions as support.