First pass of ImageWriter

Change-Id: I4f189587a2e3cc1c265200b8fa64321b299947eb
diff --git a/src/utils.h b/src/utils.h
index ddecef9..842db63 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -4,6 +4,7 @@
 #define ART_SRC_UTILS_H_
 
 #include "globals.h"
+#include "logging.h"
 #include "stringprintf.h"
 
 namespace art {
@@ -96,6 +97,8 @@
   return static_cast<int>(x & 0x0000003F);
 }
 
+#define CLZ(x) __builtin_clz(x)
+
 static inline bool NeedsEscaping(uint16_t ch) {
   return (ch < ' ' || ch > '~');
 }