Doesn't compile on Fedora 23/gcc 5.3.1

[HerbertKoelman]

Funny how compilers behave differently !!??

$ make
g++  -x c++ -std=c++11 -frtti    -I ../include -I ./ -c exceptions.cpp
exceptions.cpp:29:56: erreur : virt-specifiers in ‘what’ not allowed outside a class definition
   const char *pthread_exception::what() const noexcept override{
                                                        ^
Makefile:65: recipe for target 'exceptions.o' failed
make: *** [exceptions.o] Error 1