use of undeclared identifier '__ATOMIC_ACQ_REL' when building llvm-3.1 on Fedora 17

[Lars Seipel]

On Saturday 01 September 2012 15:06:40 Ilyes Gouta wrote:

> and this is with gcc version 4.7.0 20120507 (Red Hat 4.7.0-5) (GCC).

This doesn't look like you're building with GCC. Do you have an older version 
of clang somewhere in your path? IIRC llvm's configure script prefers to choose 
clang when it's there. Clang then chokes on the libstdc++ headers.

Lars