Name all external facing structs

Replace all anonymous structs with struct name matching current typedef
minus _t.

Change-Id: I639295e8f1bc4651fffc9286a7dba5171c92ce92
diff --git a/vpx_codec/internal/vpx_codec_internal.h b/vpx_codec/internal/vpx_codec_internal.h
index 0867552..e95d603 100644
--- a/vpx_codec/internal/vpx_codec_internal.h
+++ b/vpx_codec/internal/vpx_codec_internal.h
@@ -314,7 +314,7 @@
 };
 
 /*!\brief Callback function pointer / user data pair storage */
-typedef struct
+typedef struct vpx_codec_priv_cb_pair
 {
     union
     {
diff --git a/vpx_codec/vpx_codec.h b/vpx_codec/vpx_codec.h
index e2a79f9..d18505c 100644
--- a/vpx_codec/vpx_codec.h
+++ b/vpx_codec/vpx_codec.h
@@ -196,7 +196,7 @@
      * may reference the 'name' member to get a printable description of the
      * algorithm.
      */
-    typedef struct
+    typedef struct vpx_codec_ctx
     {
         const char              *name;        /**< Printable interface name */
         vpx_codec_iface_t       *iface;       /**< Interface pointers */
diff --git a/vpx_codec/vpx_decoder.h b/vpx_codec/vpx_decoder.h
index 5e4968d..ab0818f 100644
--- a/vpx_codec/vpx_decoder.h
+++ b/vpx_codec/vpx_decoder.h
@@ -68,7 +68,7 @@
      * stream. Algorithms may extend this structure with data specific
      * to their bitstream by setting the sz member appropriately.
      */
-    typedef struct
+    typedef struct vpx_codec_stream_info
     {
         unsigned int sz;     /**< Size of this structure */
         unsigned int w;      /**< Width (or 0 for unknown/default) */
diff --git a/vpx_codec/vpx_image.h b/vpx_codec/vpx_image.h
index a8a9416..09def8f 100644
--- a/vpx_codec/vpx_image.h
+++ b/vpx_codec/vpx_image.h
@@ -60,7 +60,7 @@
 
 
     /**\brief Image Descriptor */
-    typedef struct
+    typedef struct vpx_image
     {
         img_fmt_t     fmt; /**< Image Format */