Like so:
Undefined symbols for architecture x86_64:
"sf::RenderWindow::RenderWindow(sf::VideoMode, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, unsigned int, sf::ContextSettings const&)", referenced from:
_main in main.o
"sf::Font::loadFromFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main.o
"sf::Music::openFromFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
_main in main.o
"sf::String::String(char const*, std::__1::locale const&)", referenced from:
_main in main.o
"sf::Texture::loadFromFile(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, sf::Rect<int> const&)", referenced from:
_main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
I assume it's every SFML function called in the template program.