EmulatorPkg: Make the library work with DXE Core.

The DXE core calls library constructors after it calls DEBUG macros, so we need more error handling in the lib.

signed-off-by: andrewfish



git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12118 6f19259b-4bc3-4df7-8a09-765794883524

EmulatorPkg/Library/DxeEmuStdErrSerialPortLib/DxeEmuStdErrSerialPortLib.c

@@ -66,6 +66,10 @@ SerialPortWrite (
   IN UINTN     NumberOfBytes
   )
 {
+  if (gEmuThunk == NULL) {
+    return NumberOfBytes;
+  }
+  
   return gEmuThunk->WriteStdErr (Buffer, NumberOfBytes);
 }