protonmail-bridge: split into multiple files

pkgs/applications/networking/protonmail-bridge/headless.nix

@@ -0,0 +1,30 @@
+{}:
+
+rec {
+  pname = "protonmail-bridge-headless";
+
+  tags = "pmapi_prod nogui";
+
+  # FIXME: There's something fucky going on in the buildFlagsArray
+  # substitution. I shouldn't need to do this.
+  buildPhase =
+    let
+      t = "github.com/ProtonMail/proton-bridge/pkg/constants";
+    in
+    ''
+      runHook preBuild
+
+      go install \
+        -tags="${tags}" \
+        -ldflags="-X ${t}.Version=1.3.2 -X ${t}.Revision=unknown -X ${t}.BuildDate=unknown" \
+        cmd/Desktop-Bridge/main.go
+      mv $GOPATH/bin/main $GOPATH/bin/Desktop-Bridge
+        
+      runHook postBuild
+    '';
+
+  # Fix up name.
+  postInstall = ''
+    mv $out/bin/Desktop-Bridge $out/bin/protonmail-bridge
+  '';
+}