Add fallback for hostname if uname isn't available. (#12655)

Merged-By: ioquatix <samuel@codeotaku.com>

spec/ruby/library/socket/socket/gethostname_spec.rb

@@ -2,7 +2,15 @@ require_relative '../spec_helper'
 require_relative '../fixtures/classes'
 
 describe "Socket.gethostname" do
+  def system_hostname
+    # Most platforms implement this POSIX standard:
+    `uname -n`.strip
+  rescue
+    # Only really required for Windows without MSYS/MinGW/Cygwin etc:
+    `hostname`.strip
+  end
+
   it "returns the host name" do
-    Socket.gethostname.should == `uname -n`.strip
+    Socket.gethostname.should == system_hostname
   end
 end