Add ARM 64 support.

BUG: 33.
diff --git a/src/utils.h b/src/utils.h
index 767094b..60ad86a 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -58,7 +58,8 @@
     defined(__mips__) || defined(__powerpc__) || \
     defined(__sparc__) || defined(__sparc) || defined(__s390__) || \
     defined(__SH4__) || defined(__alpha__) || \
-    defined(_MIPS_ARCH_MIPS32R2)
+    defined(_MIPS_ARCH_MIPS32R2) || \
+    defined(_AARCH64EL_)
 #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
 #elif defined(_M_IX86) || defined(__i386__) || defined(__i386)
 #if defined(_WIN32)