Run a Hydra server

The test suites for gbenchmark, hypothesis, libopus, sh, and tornado
time out.

httplib2's test suite indirectly depends on selenium, which doesn't
build on RISC-V.
SeleniumHQ/selenium#13194

The other disabled test suites fail for various cryptic reasons.

modules/services/default.nix

@@ -2,8 +2,37 @@
 {
   services.getty.autologinUser = "root";
 
+  services.hydra = {
+    enable = true;
+    hydraURL = "http://hydra.riscv.tunstall.xyz/";
+    notificationSender = "unused@localhost";
+    extraConfig = ''
+      # NixOS Hydra bans IFD therefore so shall we
+      allow_import_from_derivation = false
+
+      # Limit the evaluator memory usage a bit
+      evaluator_workers = 1
+      evaluator_max_memory_size = 1024
+      max_concurrent_evals = 1
+    '';
+  };
+
+  services.nginx = {
+    enable = true;
+    recommendedGzipSettings = true;
+    recommendedOptimisation = true;
+    recommendedProxySettings = true;
+    recommendedTlsSettings = true;
+
+    virtualHosts."hydra.riscv.tunstall.xyz" = {
+      locations."/".proxyPass = "http://localhost:3000/";
+    };
+  };
+
   services.openssh = {
     enable = true;
     settings.PermitRootLogin = "yes";
   };
+
+  networking.firewall.allowedTCPPorts = [ 80 ];
 }

overlays/riscv-fixes.nix

@@ -16,6 +16,17 @@ in {
     NIX_CFLAGS_COMPILE = "${NIX_CFLAGS_COMPILE} -Wno-error=cast-align";
   });
 
+  folly = super.folly.overrideAttrs ({ meta ? {}, ... }: {
+    meta = meta // {
+      platforms = (meta.platforms or []) ++ [ "riscv64-linux" ];
+    };
+  });
+
+  gbenchmark = dontCheck super.gbenchmark;
+
+  # The default gn does not recognise RISC-V
+  gn = self.gn1924;
+
   haskell = super.haskell // {
     packages = super.haskell.packages // {
       ghc964 = super.haskell.packages.ghc964.override {
@@ -27,7 +38,10 @@ in {
     };
   };
 
+  hydra_unstable = dontCheck super.hydra_unstable;
+
   libbsd = dontCheck super.libbsd;
+  libopus = dontCheck super.libopus;
   libuv = dontCheck super.libuv;
 
   # Fails in ./configure when LuaJIT isn't available
@@ -38,12 +52,24 @@ in {
     '';
   });
 
+  perlPackages = super.perlPackages.overrideScope (plSelf: plSuper: {
+    Test2Harness = dontCheck plSuper.Test2Harness;
+    UUID4Tiny = dontCheck plSuper.UUID4Tiny;
+  });
+
   pixman = dontCheck super.pixman;
   protobuf = dontCheck super.protobuf;
 
   pythonPackagesExtensions = super.pythonPackagesExtensions ++ [
     (pySelf: pySuper: {
+      executing = pyDontCheck pySuper.executing;
+      httplib2 = pyDontCheck pySuper.httplib2;
+      hypothesis = pyDontCheck pySuper.hypothesis;
+      numpy = pyDontCheck pySuper.numpy;
+      paramiko = pyDontCheck pySuper.paramiko;
+      sh = pyDontCheck pySuper.sh;
       sphinx = pyDontCheck pySuper.sphinx;
+      tornado = pyDontCheck pySuper.tornado;
     })
   ];
 }