--- a/dom/media/gmp/GMPChild.cpp
+++ b/dom/media/gmp/GMPChild.cpp
@@ -103,22 +103,20 @@ GetPluginFile(const nsAString& aPluginPa
               nsCOMPtr<nsIFile>& aLibDirectory,
               nsCOMPtr<nsIFile>& aLibFile)
 {
   nsAutoString baseName;
   GetFileBase(aPluginPath, aLibDirectory, aLibFile, baseName);
 
 #if defined(XP_MACOSX)
   nsAutoString binaryName = NS_LITERAL_STRING("lib") + baseName + NS_LITERAL_STRING(".dylib");
-#elif defined(OS_POSIX)
-  nsAutoString binaryName = NS_LITERAL_STRING("lib") + baseName + NS_LITERAL_STRING(".so");
 #elif defined(XP_WIN)
   nsAutoString binaryName =                            baseName + NS_LITERAL_STRING(".dll");
 #else
-#error not defined
+  nsAutoString binaryName = NS_LITERAL_STRING("lib") + baseName + NS_LITERAL_STRING(".so");
 #endif
   aLibFile->AppendRelativePath(binaryName);
   return true;
 }
 
 static bool
 GetPluginFile(const nsAString& aPluginPath,
               nsCOMPtr<nsIFile>& aLibFile)

--- a/dom/media/gmp/GMPProcessChild.cpp
+++ b/dom/media/gmp/GMPProcessChild.cpp
@@ -24,29 +24,27 @@ GMPProcessChild::~GMPProcessChild()
 {
 }
 
 bool
 GMPProcessChild::Init(int aArgc, char* aArgv[])
 {
   nsAutoString pluginFilename;
 
-#if defined(OS_POSIX)
+#if !defined(XP_WIN)
   // NB: need to be very careful in ensuring that the first arg
   // (after the binary name) here is indeed the plugin module path.
   // Keep in sync with dom/plugins/PluginModuleParent.
   std::vector<std::string> values = CommandLine::ForCurrentProcess()->argv();
   MOZ_ASSERT(values.size() >= 2, "not enough args");
   pluginFilename = NS_ConvertUTF8toUTF16(nsDependentCString(values[1].c_str()));
-#elif defined(OS_WIN)
+#else
   std::vector<std::wstring> values = CommandLine::ForCurrentProcess()->GetLooseValues();
   MOZ_ASSERT(values.size() >= 1, "not enough loose args");
   pluginFilename = nsDependentString(values[0].c_str());
-#else
-#error Not implemented
 #endif
 
   BackgroundHangMonitor::Startup();
 
   return mPlugin.Init(pluginFilename,
                       ParentPid(),
                       IOThreadChild::message_loop(),
                       IOThreadChild::channel());