explicitly define the gHead for the codec llist



git-svn-id: http://skia.googlecode.com/svn/trunk@85 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/images/SkImageDecoder_Factory.cpp b/src/images/SkImageDecoder_Factory.cpp
index 3300981..9dd9913 100644
--- a/src/images/SkImageDecoder_Factory.cpp
+++ b/src/images/SkImageDecoder_Factory.cpp
@@ -22,6 +22,8 @@
 
 typedef SkTRegistry<SkImageDecoder*, SkStream*> DecodeReg;
 
+template DecodeReg* DecodeReg::gHead;
+
 SkImageDecoder* SkImageDecoder::Factory(SkStream* stream) {
     const DecodeReg* curr = DecodeReg::Head();
     while (curr) {