Force linking for skhello.

Otherwise encoders are stripped and the program produces nothing.

git-svn-id: http://skia.googlecode.com/svn/trunk@12487 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/skhello.cpp b/tools/skhello.cpp
index d30849b..93dad56 100644
--- a/tools/skhello.cpp
+++ b/tools/skhello.cpp
@@ -9,12 +9,15 @@
 #include "SkCommandLineFlags.h"
 #include "SkData.h"
 #include "SkDocument.h"
+#include "SkForceLinking.h"
 #include "SkGraphics.h"
 #include "SkSurface.h"
 #include "SkImage.h"
 #include "SkStream.h"
 #include "SkString.h"
 
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
 DEFINE_string2(outFile, o, "skhello", "The filename to write the image.");
 DEFINE_string2(text, t, "Hello", "The string to write.");