Re: [PATCH] Add "riscv" as an alias for "riscv32"

[John Ericson]

DJ's and Karsten's concerns match my config-for-target vs 
config-for-toolchain distinction.

arm*- riscv-* and x86-* do make sense as compiler prefixes that indicate 
toolchain support for a set of targets. But when we think of a toolchain 
+ a set of standard libraries (without multilib), only a single target 
makes sense, so those 3 are all bad.

On the other hand riscv32 is bad because, as I just learned, there are 
*3* base ISAs, not *2*, and riscv32e and riscv32i are totally 
incompatible. So for targets we need riscv32e-* riscv32i-* riscv64e-*. 
riscv{32,64} may be what uname does, but uname's output is the most 
harmful of here: it's too vague for actual targets, and too specific for 
stdlib-less embedded compiler prefixes, so both camps are left wanting.

As to riscv-* I see the exact-target and toolchain use-cases as 
fundamentally irreconcilable, so GNU config should just learn the 
difference so as to satisfy everyone *without* compromise. If we can 
agree on this I volunteer to immediately do all the work---I now have 
enough information from this thread.

And finally, the original patch is no good in my mind even as a first 
incremental step, as the unconditional riscv- to riscv32- desugar is 
also wrong for embedded and desktop/distro alike.

John

P.S. Sorry to be basically repeating myself, but I think I was too wordy 
the first time / lost within the fast pace of the thread the first time 
around