This patch is sourced from Debian's mozjs24 patch set.

Description: Add arm64 support
Author: Andreas Schwab <schwab@suse.de>
Origin: vendor, https://build.opensuse.org/package/view_file/openSUSE:Factory/mozjs17/mozjs-aarch64-support.patch
Forwarded: no
Last-Update: 2014-01-03

Index: b/mfbt/double-conversion/utils.h
===================================================================
--- a/mfbt/double-conversion/utils.h
+++ b/mfbt/double-conversion/utils.h
@@ -58,7 +58,7 @@
     defined(__mips__) || defined(__powerpc__) || \
     defined(__sparc__) || defined(__sparc) || defined(__s390__) || \
     defined(__SH4__) || defined(__alpha__) || \
-    defined(_MIPS_ARCH_MIPS32R2)
+    defined(_MIPS_ARCH_MIPS32R2) || defined(__aarch64__)
 #define DOUBLE_CONVERSION_CORRECT_DOUBLE_OPERATIONS 1
 #elif defined(_M_IX86) || defined(__i386__) || defined(__i386)
 #if defined(_WIN32)