Clean up standard stream logic

Now we have enough portability stuff

src/libutil/logging.cc

@@ -38,7 +38,7 @@ void Logger::warn(const std::string & msg)
 
 void Logger::writeToStdout(std::string_view s)
 {
-    Descriptor standard_out = getStandardOut();
+    Descriptor standard_out = getStandardOutput();
     writeFull(standard_out, s);
     writeFull(standard_out, "\n");
 }
@@ -118,11 +118,7 @@ void writeToStderr(std::string_view s)
 {
     try {
         writeFull(
-#ifdef _WIN32
-            GetStdHandle(STD_ERROR_HANDLE),
-#else
-            STDERR_FILENO,
-#endif
+            getStandardError(),
             s, false);
     } catch (SystemError & e) {
         /* Ignore failing writes to stderr.  We need to ignore write