nix/compile.nix

@@ -19,9 +19,30 @@ let
       overlays = [ cargo2nixOverlay ];
     };
 
-  toolchainOptions = {
+  /* Cargo2nix is built for rustOverlay which installs Rust from Mozilla releases.
+     This is fine for 64-bit platforms, but for 32-bit platforms, we need our own Rust
+     to avoid incompatibilities with time_t between different versions of musl
+     (>= 1.2.0 shipped by NixOS, < 1.2.0 with which rustc was built), which lead to compilation breakage.
+     So we want a Rust release that is bound to our Nix repository to avoid these problems.
+     See here for more info: https://musl.libc.org/time64.html
+     Because Cargo2nix does not support the Rust environment shipped by NixOS,
+     we emulate the structure of the Rust object created by rustOverlay.
+     In practise, rustOverlay ships rustc+cargo in a single derivation while
+     NixOS ships them in separate ones. We reunite them with symlinkJoin.
+  */
+  toolchainOptions = if target == null || target == "x86_64-unknown-linux-musl"
+  || target == "aarch64-unknown-linux-musl" then {
     rustVersion = "1.73.0";
     extraRustComponents = [ "clippy" ];
+  } else {
+    rustToolchain = pkgs.symlinkJoin {
+      name = "rust-static-toolchain-${target}";
+      paths = [
+        pkgs.rustPlatform.rust.cargo
+        pkgs.rustPlatform.rust.rustc
+        # clippy not needed, it only runs on amd64
+      ];
+    };
   };
 
   buildEnv = (drv:

nix/toolchain.nix

@@ -3,9 +3,29 @@
 with import ./common.nix;
 
 let
+  platforms = [
+    #"x86_64-unknown-linux-musl"
+    "i686-unknown-linux-musl"
+    #"aarch64-unknown-linux-musl"
+    "armv6l-unknown-linux-musleabihf"
+  ];
+  pkgsList = builtins.map (target:
+    import pkgsSrc {
+      inherit system;
+      crossSystem = {
+        config = target;
+        isStatic = true;
+      };
+      overlays = [ cargo2nixOverlay ];
+    }) platforms;
   pkgsHost = import pkgsSrc { };
+  lib = pkgsHost.lib;
   kaniko = (import ./kaniko.nix) pkgsHost;
   winscp = (import ./winscp.nix) pkgsHost;
   manifestTool = (import ./manifest-tool.nix) pkgsHost;
-in [ kaniko winscp manifestTool ]
+in lib.flatten (builtins.map (pkgs: [
+  pkgs.rustPlatform.rust.rustc
+  pkgs.rustPlatform.rust.cargo
+  pkgs.buildPackages.stdenv.cc
+]) pkgsList) ++ [ kaniko winscp manifestTool ]