I'm trying to install travis on ubuntu but keeps failing. How can I solve this?
sudo gem install travis
Building native extensions. This could take a while... ERROR: Error installing travis: ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c /usr/bin/ruby2.1 -r ./siteconf20180216-3916-17dbwfe.rb extconf.rb checking for ffi.h... no checking for ffi.h in /usr/local/include,/usr/include/ffi... no checking for shlwapi.h... no checking for rb_thread_blocking_region()... yes checking for rb_thread_call_with_gvl()... yes checking for rb_thread_call_without_gvl()... yes creating extconf.h creating Makefile
current directory: /var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c make "DESTDIR=" clean
current directory: /var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c make "DESTDIR=" Running autoreconf for libffi /var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c/libffi/autogen.sh: 2: exec: autoreconf: not found libffi.mk:6: recipe for target '"/var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c/libffi-x86_64-linux-gnu"/.libs/libffi_convenience.a' failed make: *** ["/var/lib/gems/2.1.0/gems/ffi-1.9.21/ext/ffi_c/libffi-x86_64-linux-gnu"/.libs/libffi_convenience.a] Error 127
make failed, exit code 2
Gem files will remain installed in /var/lib/gems/2.1.0/gems/ffi-1.9.21 for inspection. Results logged to /var/lib/gems/2.1.0/extensions/x86_64-linux/2.1.0/ffi-1.9.21/gem_make.out
