Add compiler-specific "examine printf format" attributes to printfs.

media/filters/ffmpeg_glue.cc

Index: media/filters/ffmpeg_glue.cc
diff --git a/media/filters/ffmpeg_glue.cc b/media/filters/ffmpeg_glue.cc
index 3c8433c36d5b0d5cea76370be81452f20715a36e..77b1f335ab8cc3de9847e4bdc9b3ff82a23ff7ba 100644
--- a/media/filters/ffmpeg_glue.cc
+++ b/media/filters/ffmpeg_glue.cc
@@ -151,7 +151,7 @@ std::string FFmpegGlue::GetProtocolKey(FFmpegURLProtocol* protocol) {
   // Use the FFmpegURLProtocol's memory address to generate the unique string.
   // This also has the nice property that adding the same FFmpegURLProtocol
   // reference will not generate duplicate entries.
-  return StringPrintf("%s://0x%lx", kProtocol, static_cast<void*>(protocol));
+  return StringPrintf("%s://%p", kProtocol, static_cast<void*>(protocol));
 }
 
 }  // namespace media