 
                            
                            
                            Rails安装mysql2 gem报错:Failed to build gem native extension.
                            
                         
                        
                    
                                        
                        
                            
                                 
                            
                            
                            Ruby gem 'pg' 报错:Gem::LoadError can't activate pg (~> 0.18), already activated pg-1.0.0. Make sure all dependencies are added to Gemfile.
                            
                         
                        
                    
                                        
                        
                            
                                 
                            
                            
                            安装compass时出现ERROR: Failed to build gem native extension...... -- mkmf (Load Error)解决办法
                            
                         
                        
                    
                                        
                        
                            
                                 
                            
                            
                            Rails安装mysql2 gem报错:Failed to build gem native extension.
                            
                         
                        
                    
                                        
                        
                            
                                 
                            
                            
                            Ruby gem 'pg' 报错:Gem::LoadError can't activate pg (~> 0.18), already activated pg-1.0.0. Make sure all dependencies are added to Gemfile.