Work around incompatibility between various C++ standard libs in C++14 mode on…

Work around incompatibility between various C++ standard libs in C++14 mode on some Linux distros, including Ubuntu 14.04.

c++/src/kj/common.h

@@ -77,6 +77,14 @@
 #include <stddef.h>
 #include <initializer_list>
 
+#if __linux__ && __cplusplus > 201200L
+// Hack around stdlib bug with C++14 that exists on some Linux systems.
+// Apparently in this mode the C library decides not to define gets() but the C++ library still
+// tries to import it into the std namespace. This bug has been fixed at the source but is still
+// widely present in the wild e.g. on Ubuntu 14.04.
+#undef _GLIBCXX_HAVE_GETS
+#endif
+
 // =======================================================================================
 
 namespace kj {