http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52929
Andrew Macleod <amacleod at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amacleod at redhat dot com
--- Comment #2 from Andrew Macleod <amacleod at redhat dot com> 2012-04-10
20:18:01 UTC ---
It is built in to the C preprocessor as a predefined value in GCC 4.7 (see
cppbuiltin.c), so you wouldn't find a specific #define anywhere.
The __atomic built-ins don't work properly without at least a GCC 4.7 compiler,
so you wouldn't be able to compile them properly with a different compiler.
