Fix build under gcc 7.0.

PiperOrigin-RevId: 270655570

cc/subtle/BUILD.bazel

@@ -538,6 +538,7 @@ cc_library(
     hdrs = ["common_enums.h"],
     include_prefix = "tink",
     strip_include_prefix = "/cc",
+    deps = ["@com_google_absl//absl/strings"],
 )
 
 cc_library(

cc/subtle/CMakeLists.txt

@@ -478,6 +478,8 @@ tink_cc_library(
   SRCS
     common_enums.cc
     common_enums.h
+  DEPS
+    absl::strings
 )
 
 tink_cc_library(

cc/subtle/common_enums.cc

@@ -18,6 +18,8 @@
 
 #include <string>
 
+#include "absl/strings/str_cat.h"
+
 namespace crypto {
 namespace tink {
 namespace subtle {
@@ -35,7 +37,7 @@ std::string EnumToString(EllipticCurveType type) {
   case EllipticCurveType::UNKNOWN_CURVE:
     return "UNKNOWN_CURVE";
   default:
-    return "UNKNOWN_CURVE: " + std::to_string(type);
+    return absl::StrCat("UNKNOWN_CURVE: ", type);
   }
 }
 
@@ -50,7 +52,7 @@ std::string EnumToString(EcPointFormat format) {
   case EcPointFormat::UNKNOWN_FORMAT:
     return "UNKNOWN_FORMAT";
   default:
-    return "UNKNOWN_FORMAT: " + std::to_string(format);
+    return absl::StrCat("UNKNOWN_FORMAT: ", format);
   }
 }
 
@@ -67,7 +69,7 @@ std::string EnumToString(HashType type) {
   case HashType::UNKNOWN_HASH:
     return "UNKNOWN_HASH";
   default:
-    return "UNKNOWN_HASH: " + std::to_string(type);
+    return absl::StrCat("UNKNOWN_HASH: ", type);
   }
 }
 

cc/util/BUILD.bazel

@@ -2,7 +2,6 @@ package(default_visibility = ["//tools/build_defs:internal_pkg"])
 
 licenses(["notice"])
 
-
 cc_library(
     name = "buffer",
     srcs = ["buffer.cc"],
@@ -62,7 +61,8 @@ cc_library(
     visibility = ["//visibility:public"],
     deps = [
         "@com_google_absl//absl/base:core_headers",
-    ]
+        "@com_google_absl//absl/strings",
+    ],
 )
 
 cc_library(

cc/util/CMakeLists.txt

@@ -49,6 +49,7 @@ tink_cc_library(
     status.h
   DEPS
     absl::base
+    absl::strings
   PUBLIC
 )
 

cc/util/status.cc

@@ -17,6 +17,8 @@
 #include <sstream>
 
 #include "tink/util/status.h"
+
+#include "absl/strings/str_cat.h"
 // placeholder_google3_status_header, please ignore
 
 using ::std::ostream;
@@ -117,7 +119,7 @@ std::string ErrorCodeString(crypto::tink::util::error::Code error) {
   }
   // Avoid using a "default" in the switch, so that the compiler can
   // give us a warning, but still provide a fallback here.
-  return std::to_string(error);
+  return absl::StrCat(error);
 }
 
 extern ostream& operator<<(ostream& os, crypto::tink::util::error::Code code) {