Draft: Specialise NOINLINE definitions in -fspecialise-aggressively mode
Based on @simonpj's comment at #21036 (comment 407930), this MR enables specialization of NOINLINE
definitions by postponing the generated RULE
s to after programmer-originating ones.
Note that for cross-module specialization of NOINLINE
things, you'll also want to use -fexpose-all-unfoldings
since otherwise outside definitions won't have a template to generate the specialization from.