Build with -std=gnu++98 What broke the build is that gcc 6 changed the default C++ standard from C++98 to C++14. . Not all valid C++98 code is also valid C++11 and C++14 code. . Note that this just changed the default, when told to process C++98 code gcc 6 does not differ in any significant way from gcc 5. . Making the code compatible with C++14 would be the best possible solution, but as a workaround it is possible to fix the build with this change to tell gcc that this is C++98 code. . The CXXFLAGS handling in configure.in is wrong and prevents passing flags the normal way, as a workaround this patches configure.in
