Add support for MIPS64.

Change-Id: I78e27bf942b4a825543e76be25546b6458bad8b6
diff --git a/configure b/configure
index 92ca061..2708b45 100755
--- a/configure
+++ b/configure
@@ -111,6 +111,7 @@
 all_platforms="${all_platforms} armv7-win32-vs12"
 all_platforms="${all_platforms} armv7s-darwin-gcc"
 all_platforms="${all_platforms} mips32-linux-gcc"
+all_platforms="${all_platforms} mips64-linux-gcc"
 all_platforms="${all_platforms} ppc32-darwin8-gcc"
 all_platforms="${all_platforms} ppc32-darwin9-gcc"
 all_platforms="${all_platforms} ppc32-linux-gcc"
@@ -254,6 +255,8 @@
     mips32
     dspr2
 
+    mips64
+
     mmx
     sse
     sse2