diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index a3521d5590..bd4d1dd6da 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -1981,6 +1981,9 @@ class Formula
       import site; site.addsitedir("#{HOMEBREW_PREFIX}/lib/python2.7/site-packages")
       import sys, os; sys.path = (os.environ["PYTHONPATH"].split(os.pathsep) if "PYTHONPATH" in os.environ else []) + ["#{HOMEBREW_PREFIX}/lib/python2.7/site-packages"] + sys.path
     PYTHON
+
+    # Don't let bazel write to tmp directories we don't control or clean.
+    (home/".bazelrc").write "startup --output_user_root=#{home}/_bazel"
   end
 
   # Returns a list of Dependency objects that are declared in the formula.
diff --git a/Library/Homebrew/mktemp.rb b/Library/Homebrew/mktemp.rb
index fb1eeb5397..fbfc7ef627 100644
--- a/Library/Homebrew/mktemp.rb
+++ b/Library/Homebrew/mktemp.rb
@@ -62,9 +62,23 @@ class Mktemp
     begin
       Dir.chdir(tmpdir) { yield self }
     ensure
-      ignore_interrupts { rm_rf(tmpdir) } unless retain?
+      ignore_interrupts { chmod_rm_rf(tmpdir) } unless retain?
     end
   ensure
     ohai "Temporary files retained at:", @tmpdir.to_s if retain? && !@tmpdir.nil? && !@quiet
   end
+
+  private
+
+  def chmod_rm_rf(path)
+    if path.directory? && !path.symlink?
+      chmod("u+rw", path) if path.owned? # Need permissions in order to see the contents
+      path.children.each { |child| chmod_rm_rf(child) }
+      rmdir(path)
+    else
+      rm_f(path)
+    end
+  rescue
+    nil # Just skip this directory.
+  end
 end