Process: Add sys::Process::FileDescriptorHasColors().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160557 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index 4e1bd5d..174112e 100644
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -249,16 +249,18 @@
   return false;
 }
 
+bool Process::FileDescriptorHasColors(int fd) {
+  // A file descriptor has colors if it is displayed and the terminal has
+  // colors.
+  return FileDescriptorIsDisplayed(fd) && terminalHasColors();
+}
+
 bool Process::StandardOutHasColors() {
-  if (!StandardOutIsDisplayed())
-    return false;
-  return terminalHasColors();
+  return FileDescriptorHasColors(STDOUT_FILENO);
 }
 
 bool Process::StandardErrHasColors() {
-  if (!StandardErrIsDisplayed())
-    return false;
-  return terminalHasColors();
+  return FileDescriptorHasColors(STDERR_FILENO);
 }
 
 bool Process::ColorNeedsFlush() {