Roll opus to opus-HEAD-66611f1.

third_party/opus/opus.gyp

Index: third_party/opus/opus.gyp
diff --git a/third_party/opus/opus.gyp b/third_party/opus/opus.gyp
index b64f9903ca006a15117cd437afbe14adc69f58e0..5fdeea6e230ea7176fcf06f392a8bf27107c2d58 100644
--- a/third_party/opus/opus.gyp
+++ b/third_party/opus/opus.gyp
@@ -5,7 +5,9 @@
 {
   'variables': {
     'conditions': [
-      ['target_arch=="arm" or target_arch=="arm64"', {
+      # TODO(wtc): change "mipselx" to "mipsel" in this file when the
+      # compilation errors in the MIPS optimizations are fixed.
+      ['target_arch=="arm" or target_arch=="arm64" or target_arch=="mipselx"', {
         'use_opus_fixed_point%': 1,
       }, {
         'use_opus_fixed_point%': 0,
@@ -15,6 +17,11 @@
       }, {
         'use_opus_arm_optimization%': 0,
       }],
+      ['target_arch=="mipselx"', {
+        'use_opus_mips_optimization%': 1,
+      }, {
+        'use_opus_mips_optimization%': 0,
+      }],
       ['target_arch=="arm" and (OS=="win" or OS=="android" or OS=="linux")', {
         # Based on the conditions in celt/arm/armcpu.c:
         # defined(_MSC_VER) || defined(__linux__).
@@ -124,6 +131,16 @@
                 }],
               ],
             }],
+            ['use_opus_mips_optimization==1', {
+              'defines': [
+                'MIPSr1_ASM',
+                'USE_ALLOCA',
+              ],
+
+              'includes': [
+                'opus_srcs_mips.gypi',
+              ],
+            }],
           ],
         }],
       ],