I used the same SFML directory I first used when I installed it with github, and some things were removed, but now I get that:
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::String(std::basic_string<unsigned int, std::char_traits<unsigned int>, std::allocator<unsigned int> > const&)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::String(std::string const&, std::locale const&)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::Shader::loadFromMemory(std::string const&, std::string const&)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::toAnsiString(std::locale const&) const'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::end()'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::begin() const'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::end() const'
/usr/local/lib/libsfgui.so: undefined reference to `sf::Font::loadFromFile(std::string const&)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::Shader::setParameter(std::string const&, sf::Texture const&)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::String::begin()'
/usr/local/lib/libsfgui.so: undefined reference to `sf::Shader::setParameter(std::string const&, float, float)'
/usr/local/lib/libsfgui.so: undefined reference to `sf::Image::loadFromFile(std::string const&)'
collect2: error: ld returned 1 exit status
Makefile:211: recipe for target 'Menu' failed
make: *** [Menu] Error 1
Do you think I should re-download the whole directory from github?