Always `chmod +x` `binary` stanzas.

Library/Homebrew/cask/lib/hbc/artifact/binary.rb

@@ -6,6 +6,11 @@ module Hbc
       def install_phase
         super if CLI.binaries?
       end
+
+      def link(artifact_spec)
+        super(artifact_spec)
+        FileUtils.chmod "+x", source
+      end
     end
   end
 end

Library/Homebrew/cask/lib/hbc/artifact/relocated.rb

@@ -35,7 +35,7 @@ module Hbc
         altnames = "(#{altnames})"
 
         # Some packges are shipped as u=rx (e.g. Bitcoin Core)
-        @command.run!("/bin/chmod", args: ["--", "u=rwx", file.to_s, file.realpath.to_s])
+        @command.run!("/bin/chmod", args: ["--", "u+rw", file.to_s, file.realpath.to_s])
 
         @command.run!("/usr/bin/xattr",
                       args:         ["-w", ALT_NAME_ATTRIBUTE, altnames, file.to_s],

Library/Homebrew/test/cask/artifact/binary_spec.rb

@@ -9,9 +9,11 @@ describe Hbc::Artifact::Binary, :cask do
   let(:expected_path) {
     Hbc.binarydir.join("binary")
   }
+
   before(:each) do
     Hbc.binarydir.mkpath
   end
+
   after(:each) do
     FileUtils.rm expected_path if expected_path.exist?
   end
@@ -24,6 +26,17 @@ describe Hbc::Artifact::Binary, :cask do
     expect(expected_path.readlink).to exist
   end
 
+  it "makes the binary executable" do
+    expect(FileUtils).to receive(:chmod).with("+x", cask.staged_path.join("binary"))
+
+    shutup do
+      Hbc::Artifact::Binary.new(cask).install_phase
+    end
+
+    expect(expected_path).to be_a_symlink
+    expect(expected_path.readlink).to be_executable
+  end
+
   it "avoids clobbering an existing binary by linking over it" do
     FileUtils.touch expected_path