Disable libmvec

[Jonathan Wakely]

On 31 January 2017 at 13:44, Rei Y. wrote:
> From 2.22, glibc added libmvec and, as I understood it inspecting the
> executables, gcc emits code that requires it when certain
> optimizations are turned on* and the host libc supports mathvec.
> Executables compiled in such a way cannot be linked, at runtime, with
> older versions of glibc as they obviously lack libmvec. Since I cannot
> recompile the user's glibc (with --disable-mathvec) and that some
> distros, debian stable in particular, still ship with pre-2.22 glibc,
> there should be a way to disable that behavior from gcc without having
> to setup a whole environment and toolchain with an older glibc.

If you want executables that will run with an older glibc then that's
what you need to do.