lib/systems: Add Genode platform definitions

Add platform definitions for 64-bit ARM and x86. This is sufficient for
for building Genode where a toolchain is provided as an overlay.

Toolchain: git+https://git.sr.ht/~ehmry/genodepkgs?rev=14fc773ac9ecd2cbb30cb4612b284eee83d83546

lib/systems/default.nix

@@ -65,6 +65,7 @@ rec {
           freebsd = "FreeBSD";
           openbsd = "OpenBSD";
           wasi = "Wasi";
+          genode = "Genode";
         }.${final.parsed.kernel.name} or null;
 
          # uname -p

lib/systems/doubles.nix

@@ -35,6 +35,8 @@ let
     "vc4-none"
 
     "js-ghcjs"
+
+    "aarch64-genode" "x86_64-genode"
   ];
 
   allParsed = map parse.mkSystemFromString all;
@@ -68,6 +70,7 @@ in {
   unix    = filterDoubles predicates.isUnix;
   wasi    = filterDoubles predicates.isWasi;
   windows = filterDoubles predicates.isWindows;
+  genode  = filterDoubles predicates.isGenode;
 
   embedded = filterDoubles predicates.isNone;
 

lib/systems/inspect.nix

@@ -47,6 +47,7 @@ rec {
     isMinGW        = { kernel = kernels.windows; abi = abis.gnu; };
     isWasi         = { kernel = kernels.wasi; };
     isGhcjs        = { kernel = kernels.ghcjs; };
+    isGenode       = { kernel = kernels.genode; };
     isNone         = { kernel = kernels.none; };
 
     isAndroid      = [ { abi = abis.android; } { abi = abis.androideabi; } ];

lib/systems/parse.nix

@@ -279,6 +279,7 @@ rec {
     wasi    = { execFormat = wasm;    families = { }; };
     windows = { execFormat = pe;      families = { }; };
     ghcjs   = { execFormat = unknown; families = { }; };
+    genode  = { execFormat = elf;     families = { }; };
   } // { # aliases
     # 'darwin' is the kernel for all of them. We choose macOS by default.
     darwin = kernels.macos;
@@ -395,6 +396,8 @@ rec {
         then { cpu = elemAt l 0; vendor = "unknown"; kernel = elemAt l 1; abi = elemAt l 2; }
       else if (elemAt l 2 == "ghcjs")
         then { cpu = elemAt l 0; vendor = "unknown"; kernel = elemAt l 2; }
+      else if hasPrefix "genode" (elemAt l 2)
+        then { cpu = elemAt l 0; vendor = elemAt l 1; kernel = elemAt l 2; }
       else throw "Target specification with 3 components is ambiguous";
     "4" =    { cpu = elemAt l 0; vendor = elemAt l 1; kernel = elemAt l 2; abi = elemAt l 3; };
   }.${toString (length l)}