Cross compile for ARMv7, Aarch64 and RISC-V 64

Adds CI cross-compilation tests for those architectures. Requires the
host to be able to run thos binaries via binfmt.

See: https://docs.kernel.org/admin-guide/binfmt-misc.html

.gitlab-ci.yml

@@ -55,3 +55,24 @@ build:compilers:
     - nix
   script:
     - nix build -L --no-link .#ovniPackages.compilers
+
+build:armv7:
+  stage: build
+  tags:
+    - nix
+  script:
+    - nix build -L --no-link .#ovniPackages.armv7
+
+build:aarch64:
+  stage: build
+  tags:
+    - nix
+  script:
+    - nix build -L --no-link .#ovniPackages.aarch64
+
+build:riscv64:
+  stage: build
+  tags:
+    - nix
+  script:
+    - nix build -L --no-link .#ovniPackages.riscv64

flake.nix

@@ -135,6 +135,33 @@
           export ASAN_OPTIONS=detect_leaks=0
         '';
       });
+
+      armv7 = (pkgs.pkgsCross.armv7l-hf-multiplatform.ovniLocal.overrideAttrs (old: {
+        pname = "ovni-armv7";
+        buildInputs = [];
+        nativeBuildInputs = [ pkgs.pkgsCross.armv7l-hf-multiplatform.buildPackages.cmake ];
+        cmakeFlags = old.cmakeFlags ++ [ "-DUSE_MPI=OFF" ];
+      })).overrideDerivation (old: {
+        doCheck = true;
+      });
+
+      aarch64 = (pkgs.pkgsCross.aarch64-multiplatform.ovniLocal.overrideAttrs (old: {
+        pname = "ovni-aarch64";
+        buildInputs = [];
+        nativeBuildInputs = [ pkgs.pkgsCross.aarch64-multiplatform.buildPackages.cmake ];
+        cmakeFlags = old.cmakeFlags ++ [ "-DUSE_MPI=OFF" ];
+      })).overrideDerivation (old: {
+        doCheck = true;
+      });
+
+      riscv64 = (pkgs.pkgsCross.riscv64.ovniLocal.overrideAttrs (old: {
+        pname = "ovni-riscv64";
+        buildInputs = [];
+        nativeBuildInputs = [ pkgs.pkgsCross.riscv64.buildPackages.cmake ];
+        cmakeFlags = old.cmakeFlags ++ [ "-DUSE_MPI=OFF" ];
+      })).overrideDerivation (old: {
+        doCheck = true;
+      });
     };
   };
 }