JLL-style LibSuiteSparse headers are incompatible with new platforms

[maleadt]

During bringup of Julia on a non BB-supported platform, i.e., compiling Julia with USE_BINARYBUILDER := 0, I ran into the fact that SparseArrays.jl's LibSuiteSparse.jl behaves pretty much like a JLL, in that it only supports a fixed set of platforms:

SparseArrays.jl/src/solvers/LibSuiteSparse.jl

Lines 33 to 39 in ac5c8ed

	elseif Sys.isbsd() && !Sys.isapple()
	include("lib/x86_64-unknown-freebsd.jl")
	elseif Sys.iswindows() && Sys.ARCH === :x86_64
	include("lib/x86_64-w64-mingw32.jl")
	else
	error("Unknown platform: $(Base.BUILD_TRIPLET)")
	end

This seems needlessly complicated, especially because the headers are in fact identical:

❯ md5sum *
7de9f4584578f167cc12bf5000883b8c  aarch64-apple-darwin20.jl
7de9f4584578f167cc12bf5000883b8c  aarch64-linux-gnu.jl
7de9f4584578f167cc12bf5000883b8c  aarch64-linux-musl.jl
7de9f4584578f167cc12bf5000883b8c  armv7l-linux-gnueabihf.jl
7de9f4584578f167cc12bf5000883b8c  armv7l-linux-musleabihf.jl
7de9f4584578f167cc12bf5000883b8c  i686-linux-gnu.jl
7de9f4584578f167cc12bf5000883b8c  i686-linux-musl.jl
7de9f4584578f167cc12bf5000883b8c  i686-w64-mingw32.jl
7de9f4584578f167cc12bf5000883b8c  powerpc64le-linux-gnu.jl
7de9f4584578f167cc12bf5000883b8c  x86_64-apple-darwin14.jl
7de9f4584578f167cc12bf5000883b8c  x86_64-linux-gnu.jl
7de9f4584578f167cc12bf5000883b8c  x86_64-linux-musl.jl
7de9f4584578f167cc12bf5000883b8c  x86_64-unknown-freebsd.jl
7de9f4584578f167cc12bf5000883b8c  x86_64-w64-mingw32.jl

As we still support building Julia without BB support (and we probably always will), can we get rid of this complexity and move to a single libsuitesparse.jl header? Or am I missing anything?

[ViralBShah]

This is just what the clang.jl script generates, which was written a while ago. We can make it generate something simpler.

[maleadt]

I see. I'll create a PR to simplify it then.

[ViralBShah]

It's being done here:

SparseArrays.jl/gen/generator.jl

Line 27 in ac5c8ed

for target in JLLEnvs.JLL_ENV_TRIPLES