[PATCH 1/2] eal: provide macro for GCC builtin constant intrinsic

[Morten Brørup]

> From: Tyler Retzlaff [mailto:roretzla at linux.microsoft.com]
> Sent: Wednesday, 20 March 2024 22.34
> 
> MSVC does not have a __builtin_constant_p intrinsic so provide
> __rte_constant(e) that expands false for MSVC and to the intrinsic for
> GCC.
> 
> Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
> ---

Reviewed-by: Morten Brørup <mb at smartsharesystems.com>