nix(ldfi2): patchelf the dynamically linked libraries on linux

default.nix

@@ -29,12 +29,20 @@ stdenv.mkDerivation {
   pname = "detsys";
   version = "latest";
 
-  # NOTE: We cannot use `gitignoreSource` here, because the `bazel-bin`
-  # directory which we need to read from is ignored by git.
-  src = ./.;
+  # NOTE: When a `go_binary` is compiled with gotags it for some reason ends up
+  # in `bazel-out` rather than `bazel-bin`, which is why we need to add both
+  # below.
+  #
+  # TODO(stevan): k8-fastbuild-ST-578d10beb4b5 is probably unique to my machine,
+  # need to figure out how to get this path in a generic way in bazel.
+  src = if nix-build-all
+        then []
+        else [ ./bazel-bin/src ./bazel-out/k8-fastbuild-ST-578d10beb4b5/bin ];
 
   phases = [ "installPhase" "installCheckPhase" ];
 
+  nativeBuildInputs = if stdenv.isLinux then [ patchelf ] else [];
+
   propagatedBuildInputs = [ z3 ]
                           ++ lib.optional (nix-build-all || nix-build-checker)   [ checker ]
                           ++ lib.optional (nix-build-all || nix-build-cli)       [ cli ]
@@ -48,30 +56,34 @@ stdenv.mkDerivation {
   installPhase = ''
     mkdir -p $out/bin
 
+    # TODO(stevan): Is there a nicer way to access the two source directories?
+    export bazelBin="$(echo $src | cut -d ' ' -f 1)"
+    export bazelOut="$(echo $src | cut -d ' ' -f 2)"
+
     ${if nix-build-checker || nix-build-all then ''
     install -D ${checker.out}/bin/detsys-checker $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/checker/checker-bin $out/bin/detsys-checker
+    install -D $bazelBin/checker/checker-bin $out/bin/detsys-checker
     ''
     }
     ${if nix-build-cli || nix-build-all then ''
     install -D ${cli.out}/bin/detsys $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/cli/cli_/cli $out/bin/detsys
+    install -D $bazelBin/cli/cli_/cli $out/bin/detsys
     ''
     }
     ${if nix-build-db || nix-build-all then ''
     install -D ${db.out}/bin/detsys-db $out/bin
     cp -R ${db.out}/migrations $out
     '' else ''
-    install -D $src/bazel-bin/src/db/db_/db $out/bin/detsys-db
+    install -D $bazelBin/db/db_/db $out/bin/detsys-db
     # TODO(stevan): migrations need to be stored somewhere...
     ''
     }
     ${if nix-build-debugger || nix-build-all then ''
     install -D ${debugger.out}/bin/detsys-debug $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/debugger/cmd/detsys-debug/detsys-debug_/detsys-debug \
+    install -D $bazelOut/src/debugger/cmd/detsys-debug/detsys-debug_/detsys-debug \
                $out/bin/detsys-debug
     ''
     }
@@ -85,19 +97,28 @@ stdenv.mkDerivation {
     ${if nix-build-ldfi || nix-build-all then ''
     install -D ${ldfi.out}/bin/detsys-ldfi $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/ldfi2/ldfi2 $out/bin/detsys-ldfi
+    install -D $bazelBin/ldfi2/ldfi2 $out/bin/detsys-ldfi
+    ${lib.optionalString stdenv.isLinux ''
+         patchelf --set-interpreter $(cat $NIX_CC/nix-support/dynamic-linker) \
+                  "$out/bin/detsys-ldfi"
+         rpath=${lib.makeLibraryPath [ z3 stdenv.cc.cc gmp libffi ]}
+         patchelf --set-rpath "$out/lib:$rpath" \
+                  "$out/bin/detsys-ldfi"
+         ''
+     }
+     # TODO(stevan): Darwin probably needs fixing as well?
     ''
     }
     ${if nix-build-ltl || nix-build-all then ''
     install -D ${ltl.out}/bin/detsys-ltl $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/ltl/ltl $out/bin/detsys-ltl
+    install -D $bazelBin/ltl/ltl $out/bin/detsys-ltl
     ''
     }
     ${if nix-build-scheduler || nix-build-all then ''
     install -D ${scheduler.out}/bin/detsys-scheduler $out/bin
     '' else ''
-    install -D $src/bazel-bin/src/scheduler/scheduler-bin $out/bin/detsys-scheduler
+    install -D $bazelBin/scheduler/scheduler-bin $out/bin/detsys-scheduler
     ''
     }
   '';