fix android compilation (#372)

src/benchmark_register.cc

@@ -31,6 +31,7 @@
 #include <fstream>
 #include <iostream>
 #include <memory>
+#include <sstream>
 #include <thread>
 
 #include "check.h"
@@ -163,8 +164,8 @@ bool BenchmarkFamilies::FindBenchmarks(
                   StringPrintF("%s:", family->arg_names_[arg_i].c_str());
             }
           }
-
-          instance.name += std::to_string(arg);
+          
+          instance.name += StringPrintF("%d", arg);
           ++arg_i;
         }
 

src/colorprint.cc

@@ -89,7 +89,7 @@ std::string FormatString(const char* msg, va_list args) {
 
   std::size_t size = 256;
   char local_buff[256];
-  auto ret = std::vsnprintf(local_buff, size, msg, args_cp);
+  auto ret = vsnprintf(local_buff, size, msg, args_cp);
 
   va_end(args_cp);
 
@@ -104,7 +104,7 @@ std::string FormatString(const char* msg, va_list args) {
     // we did not provide a long enough buffer on our first attempt.
     size = (size_t)ret + 1;  // + 1 for the null byte
     std::unique_ptr<char[]> buff(new char[size]);
-    ret = std::vsnprintf(buff.get(), size, msg, args);
+    ret = vsnprintf(buff.get(), size, msg, args);
     CHECK(ret > 0 && ((size_t)ret) < size);
     return buff.get();
   }

test/register_benchmark_test.cc

@@ -114,14 +114,14 @@ void TestRegistrationAtRuntime() {
 #endif
 #ifndef BENCHMARK_HAS_NO_VARIADIC_REGISTER_BENCHMARK
   {
-    int x = 42;
+    const char* x = "42";
     auto capturing_lam = [=](benchmark::State& st) {
       while (st.KeepRunning()) {
       }
-      st.SetLabel(std::to_string(x));
+      st.SetLabel(x);
     };
     benchmark::RegisterBenchmark("lambda_benchmark", capturing_lam);
-    AddCases({{"lambda_benchmark", "42"}});
+    AddCases({{"lambda_benchmark", x}});
   }
 #endif
 }