Minimum GCC version for building glibc

[Carlos O'Donell]

On 11/05/2014 11:34 AM, Joseph Myers wrote:
> My inclination is to keep rolling our own.  I suspect libatomic might be 
> troublesome in bootstrap builds (where the desire is for glibc built with 
> an initial static-only GCC, itself built without C library headers, to be 
> identical to glibc built from a longer iteration of alternating GCC and 
> glibc builds).  And any libatomic operations based on locks (e.g. the 
> operations for arbitrary-sized types) obviously aren't suitable for glibc 
> use (depending as they do on pthread_mutex_lock).

My inclination is also to keep rolling our own.
 
I already share code between gcc and glibc for atomics, but the split
allows for much much easier bootstrap.

Cheers,
Carlos.