support building the aarch64 cross-compiler on macOS - #168
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Pass AR and RANLIB to the nolibc and openlibm sub-makes so they use the toolchain archiver (llvm-ar/ranlib) instead of the host default, and add -Wno-asm-operand-widths to the nolibc CFLAGS for clang. On macOS, build the cross OCaml with --othertoolprefix=llvm-, --enable-imprecise-c99-float-ops and --disable-function-sections, drop the native solo5 dependency (which has no macOS build), and mark macos/arm64 as an available platform.
The generated aarch64-solo5-ocaml-<tool> wrappers exec'd the bare tool name (e.g. llvm-ar via --othertoolprefix), so they only worked when that tool's directory was on PATH. On macOS the LLVM binutils live outside the Solo5 toolchain and the opam switch, so a plain `dune build -x` failed to find them. Bake the absolute path that command -v already returns.
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Build the aarch64 cross-compiler (pinning Solo5/solo5#641) and cross-build zarith with it: install ocaml-gmp (mirage/ocaml-gmp#29) for its relocatable gmp.pc, then point OCAMLC/OCAMLOPT/... at `ocamlfind -toolchain solo5` and PKG_CONFIG_PATH at that gmp.pc so zarith's configure (ocaml/Zarith#173) compiles caml_z.c with the cross cc against ocaml-gmp. Drop this commit, or the pins, once the forks are in opam.
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The second alternative was missing its operator: {= "5.4.1" | "5.5.0"}
makes opam read "5.5.0" as a bare filter (warning 66). Use
{= "5.4.1" | = "5.5.0"}, as ocaml-solo5.opam already does.
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I'd like to build aarch64 Solo5/MirageOS unikernels on an Apple Silicon Mac, instead of going through a Linux VM. This package is the OCaml cross-compiler for that target.
This PR builds it with the macOS LLVM toolchain: it passes the toolchain
ar/ranlibto the nolibc and openlibm makes, adds the matching cross OCaml configure flags, drops the nativesolo5dependency (no macOS build), and marksmacos/arm64available. The generatedaarch64-solo5-ocaml-*wrappers also resolve their tools to absolute paths, so they work offPATH.The rest of the stack:
gmp.pclibgmp.awith the crossar/ranlibOCAML*environment variables in configure