Add depends_on :linux and :macos

2 files changed, 23 insertions, 3 deletions

diff --git a/Library/Homebrew/requirements/linux_requirement.rb b/Library/Homebrew/requirements/linux_requirement.rb
new file mode 100644
index 000000000..cb4666e56
--- /dev/null
+++ b/Library/Homebrew/requirements/linux_requirement.rb
@@ -0,0 +1,9 @@
+class LinuxRequirement < Requirement
+  fatal true
+
+  satisfy(build_env: false) { OS.linux? }
+
+  def message
+    "Linux is required."
+  end
+end
diff --git a/Library/Homebrew/requirements/minimum_macos_requirement.rb b/Library/Homebrew/requirements/minimum_macos_requirement.rb
index 2cb63f740..ffe1d8f4d 100644
--- a/Library/Homebrew/requirements/minimum_macos_requirement.rb
+++ b/Library/Homebrew/requirements/minimum_macos_requirement.rb
@@ -3,18 +3,29 @@ require "requirement"
 class MinimumMacOSRequirement < Requirement
   fatal true
 
-  def initialize(tags)
-    @version = MacOS::Version.from_symbol(tags.first)
+  def initialize(tags = [])
+    @version = MacOS::Version.from_symbol(tags.first) unless tags.empty?
     super
   end
 
-  satisfy(build_env: false) { MacOS.version >= @version }
+  def minimum_version_specified?
+    OS.mac? && @version
+  end
+
+  satisfy(build_env: false) do
+    next MacOS.version >= @version if minimum_version_specified?
+    next true if OS.mac?
+    next true if @version
+    false
+  end
 
   def message
+    return "macOS is required." unless minimum_version_specified?
     "macOS #{@version.pretty_name} or newer is required."
   end
 
   def display_s
+    return "macOS is required" unless minimum_version_specified?
     "macOS >= #{@version}"
   end
 end