我正在尝试按照参考https://rubygems.org/gems/travis安装gem install travis使用travis-cli，但出现以下错误。
尝试过这里提到的解决方案https://github.com/ffi/ffi/issues/653：
brew reinstall libffi
export LDFLAGS="-L/usr/local/opt/libffi/lib"
export PKG_CONFIG_PATH="/usr/local/opt/libffi/lib/pkgconfig"
gem install travis
framework/Versions/2.3/usr/include/ruby-2.3.0/ruby.h:33:/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr /include/ruby-2.3.0/ruby/ruby.h:24:10: 致命错误: 'ruby/config.h' 文件未找到 #include "ruby/config.h" ^~~~~~~~~ ~~~~~~ 产生了 1 个错误。检查的程序是：/* begin */ 1: #include "ruby.h" 2: 3: int main(int argc, char * framework/Versions/2.3/usr/include/ruby-2.3.0/ruby.h:33:/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr /include/ruby-2.3.0/ruby/ruby.h:24:10: 致命错误: 'ruby/config.h' 文件未找到 #include "ruby/config.h" ^~~~~~~~~ ~~~~~~ 产生了 1 个错误。检查的程序是：/* begin */ 1: #include "ruby.h" 2: 3: int main(int argc, char *argv) 4: { 5: 返回 0; 6: } /结束 …