diff --git a/Library/Homebrew/dependency_collector.rb b/Library/Homebrew/dependency_collector.rb
index 0a38f0de39..7d3b90f9c6 100644
--- a/Library/Homebrew/dependency_collector.rb
+++ b/Library/Homebrew/dependency_collector.rb
@@ -63,11 +63,11 @@ class DependencyCollector
   end
 
   def cvs_dep_if_needed(tags)
-    Dependency.new("cvs", tags)
+    Dependency.new("cvs", tags) unless which("cvs")
   end
 
   def xz_dep_if_needed(tags)
-    Dependency.new("xz", tags)
+    Dependency.new("xz", tags) unless which("xz")
   end
 
   def zip_dep_if_needed(tags)
diff --git a/Library/Homebrew/extend/os/dependency_collector.rb b/Library/Homebrew/extend/os/dependency_collector.rb
index fffec1c999..56fcad31d0 100644
--- a/Library/Homebrew/extend/os/dependency_collector.rb
+++ b/Library/Homebrew/extend/os/dependency_collector.rb
@@ -1,3 +1,2 @@
 require "dependency_collector"
 require "extend/os/mac/dependency_collector" if OS.mac?
-require "extend/os/linux/dependency_collector" if OS.linux?
diff --git a/Library/Homebrew/extend/os/linux/dependency_collector.rb b/Library/Homebrew/extend/os/linux/dependency_collector.rb
deleted file mode 100644
index dc5b994b8a..0000000000
--- a/Library/Homebrew/extend/os/linux/dependency_collector.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-class DependencyCollector
-  def xz_dep_if_needed(tags)
-    Dependency.new("xz", tags) unless which("xz")
-  end
-end