Can't install on fresh Ubuntu 16.04

[abitrolly]

$ apt-get install ruby ruby-dev
$ ruby -v
ruby 2.3.1p112 (2016-04-26) [x86_64-linux-gnu]
$ gem install travis -v 1.8.8 --no-rdoc --no-ri
Building native extensions.  This could take a while...
ERROR:  Error installing travis:
        ERROR: Failed to build gem native extension.

    current directory: /var/lib/gems/2.3.0/gems/ffi-1.9.18/ext/ffi_c
/usr/bin/ruby2.3 -r ./siteconf20170607-1134-1b5l7zm.rb extconf.rb
checking for ffi.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/usr/bin/$(RUBY_BASE_NAME)2.3
        --with-ffi_c-dir
        --without-ffi_c-dir
        --with-ffi_c-include
        --without-ffi_c-include=${ffi_c-dir}/include
        --with-ffi_c-lib
        --without-ffi_c-lib=${ffi_c-dir}/lib
        --with-libffi-config
        --without-libffi-config
        --with-pkg-config
        --without-pkg-config
/usr/lib/ruby/2.3.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
        from /usr/lib/ruby/2.3.0/mkmf.rb:587:in `try_cpp'
        from /usr/lib/ruby/2.3.0/mkmf.rb:1091:in `block in have_header'
        from /usr/lib/ruby/2.3.0/mkmf.rb:942:in `block in checking_for'
        from /usr/lib/ruby/2.3.0/mkmf.rb:350:in `block (2 levels) in postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /usr/lib/ruby/2.3.0/mkmf.rb:350:in `block in postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:320:in `open'
        from /usr/lib/ruby/2.3.0/mkmf.rb:346:in `postpone'
        from /usr/lib/ruby/2.3.0/mkmf.rb:941:in `checking_for'
        from /usr/lib/ruby/2.3.0/mkmf.rb:1090:in `have_header'
        from extconf.rb:16:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/ffi-1.9.18/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /var/lib/gems/2.3.0/gems/ffi-1.9.18 for inspection.
Results logged to /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/ffi-1.9.18/gem_make.out

[Spongman]

i just get this:

$ gem install travis -v 1.8.8 --no-rdoc --no-ri
ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /var/lib/gems/2.3.0 directory.

not sure how to proceed.

[jmcdo29]

I'm running into the same issue. When I try to run sudo gem install travis -v 1.8.9 --no-rdoc --no-ri I get a failure. Looking at the mkmf.log it looks like the stdio.h file is missing somehow.

"pkg-config --exists libffi"
package configuration for libffi is not found
"gcc -o conftest -I/usr/include/x86_64-linux-gnu/ruby-2.5.0 -I/usr/include/ruby-2.5.0/ruby/backward -I/usr/include/ruby-2.5.0 -I. -Wdate-time -D_FORTIFY_SOURCE=2   -g -O2 -fdebug-prefix-map=/build/ruby2.5-VnpVLW/ruby2.5-2.5.1=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC conftest.c  -L. -L/usr/lib/x86_64-linux-gnu -L. -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fstack-protector -rdynamic -Wl,-export-dynamic     -lruby-2.5  -lpthread -lgmp -ldl -lcrypt -lm   -lc"
In file included from /usr/include/ruby-2.5.0/ruby/ruby.h:29:0,
                 from /usr/include/ruby-2.5.0/ruby.h:33,
                 from conftest.c:1:
/usr/include/ruby-2.5.0/ruby/defines.h:112:10: fatal error: stdio.h: No such file or directory
 #include <stdio.h>
          ^~~~~~~~~
compilation terminated.
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main(int argc, char **argv)
4: {
5:   return 0;
6: }
/* end */

[jmcdo29]

As it turns out for myself, I had an out-of-date version of build-essentials. Running sudo apt-get install build-essentials fixed this for me.

[BanzaiMan]

Closing in favor of #758. It no longer depends on native extensions, so the installation should be easier. If the issue persists, feel free to open a new one.