[core] Fix issues with the std:: namespace and old compilers

Specifically when building Android with GCC 4.9 (which Qt still does :-/)

1 files changed, 25 insertions, 0 deletions

diff --git a/include/mbgl/util/string.hpp b/include/mbgl/util/string.hpp
index de061647b5..82d317c620 100644
--- a/include/mbgl/util/string.hpp
+++ b/include/mbgl/util/string.hpp
@@ -1,9 +1,34 @@
 #pragma once
 
+#include <sstream>
 #include <string>
 #include <cassert>
+#include <cstdlib>
 #include <exception>
 
+// Polyfill needed by Qt when building for Android with GCC
+#if defined(__ANDROID__) && defined(__GLIBCXX__)
+
+namespace std {
+
+template <typename T>
+std::string to_string(T value)
+{
+    std::ostringstream oss;
+    oss << value;
+
+    return oss.str();
+}
+
+inline int stoi(const std::string &str)
+{
+    return atoi(str.c_str());
+}
+
+} // namespace std
+
+#endif
+
 namespace mbgl {
 namespace util {