external: import cpu_features library

Taken from https://github.com/google/cpu_features at revision
26133d3b620c2c27f31d571efd27371100f891e9

external/cpu_features/include/cpuinfo_mips.h

@@ -0,0 +1,53 @@
+// Copyright 2017 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CPU_FEATURES_INCLUDE_CPUINFO_MIPS_H_
+#define CPU_FEATURES_INCLUDE_CPUINFO_MIPS_H_
+
+#include "cpu_features_macros.h"
+
+CPU_FEATURES_START_CPP_NAMESPACE
+
+typedef struct {
+  int msa : 1;  // MIPS SIMD Architecture
+                // https://www.mips.com/products/architectures/ase/simd/
+  int eva : 1;  // Enhanced Virtual Addressing
+                // https://www.mips.com/products/architectures/mips64/
+
+  // Make sure to update MipsFeaturesEnum below if you add a field here.
+} MipsFeatures;
+
+typedef struct {
+  MipsFeatures features;
+} MipsInfo;
+
+MipsInfo GetMipsInfo(void);
+
+////////////////////////////////////////////////////////////////////////////////
+// Introspection functions
+
+typedef enum {
+  MIPS_MSA,
+  MIPS_EVA,
+  MIPS_LAST_,
+} MipsFeaturesEnum;
+
+int GetMipsFeaturesEnumValue(const MipsFeatures* features,
+                             MipsFeaturesEnum value);
+
+const char* GetMipsFeaturesEnumName(MipsFeaturesEnum);
+
+CPU_FEATURES_END_CPP_NAMESPACE
+
+#endif  // CPU_FEATURES_INCLUDE_CPUINFO_MIPS_H_