ERROR: Error installing sass: ERROR: Failed to build gem native extension - ruby

Question

I was trying to install sass. I did manage to install it via npm (1.14.1 compiled with dart2js 2.0.0), however I need to install it with Ruby (Ruby Sass 3.5.6.). Now, here is the error when I run "sudo gem install sass"
Building native extensions. This could take a while...
ERROR: Error installing sass:
ERROR: Failed to build gem native extension.
current directory: /Library/Ruby/Gems/2.3.0/gems/ffi-1.9.25/ext/ffi_c
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -r ./siteconf20181004-3909-1iytz3s.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=/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/$(RUBY_BASE_NAME)
--with-ffi_c-dir
--without-ffi_c-dir
--with-ffi_c-include
--without-ffi_c-include=${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
/System/Library/Frameworks/Ruby.framework/Versions/2.3/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
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:571:in `block in try_compile'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:524:in `with_werror'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:571:in `try_compile'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:1091:in `block in have_header'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:942:in `block in checking_for'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:350:in `block (2 levels) in postpone'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:320:in `open'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:350:in `block in postpone'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:320:in `open'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:346:in `postpone'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/
2.3.0/mkmf.rb:941:in `checking_for'
from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/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:
/Library/Ruby/Gems/2.3.0/extensions/universal-darwin-18/2.3.0/ffi-1.9.25/mkmf.log
extconf failed, exit code 1
Gem files will remain installed in /Library/Ruby/Gems/2.3.0/gems/ffi-1.9.25 for inspection.
Results logged to /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-18/2.3.0/ffi-1.9.25/gem_make.out
I have tried to update Ruby, delete sass installed via npm, update xcode dev-tools as some suggested. But nothing works. I have no idea what is the reason since I had sass before updating to new Mac OS Mojave from 0.
Here is the mkmf.log file:
package configuration for libffi is not found
"xcrun clang -o conftest -
I/System/Library/Frameworks/Ruby.framework
/Versions/2.3/usr/include/ruby-2.3.0/universal-darwin18 -
I/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/
include/ruby-2.3.0/ruby/backward -
I/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/
ruby-2.3.0 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -
D_DARWIN_UNLIMITED_SELECT -D_REENTRANT -g -Os -pipe -
DHAVE_GCC_ATOMIC_BUILTINS conftest.c -L. -
L/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib -L.
-lruby.2.3.0 -lpthread -ldl -lobjc "
In file included from conftest.c:1:
In file included from
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/
ruby-2.3.0/ruby.h:33:
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/
ruby-2.3.0/ruby/ruby.h:24:10: fatal error: 'ruby/config.h' file not found
#include "ruby/config.h"
^~~~~~~~~~~~~~~
1 error generated.
checked program was:
/* begin */
1: #include "ruby.h"
2:
3: int main(int argc, char **argv)
4: {
5: return 0;
6: }
/* end */
Any ideas?

Answer 1

Ok, so the solution was found. If you have this error. Do this:
Install rvm (https://rvm.io/)
Then I had to run this command to make rvm work:
if sudo grep -q secure_path /etc/sudoers; then sudo sh -c "echo export rvmsudo_secure_path=1 >> /etc/profile.d/rvm_secure_path.sh" && echo Environment variable installed; fi
next with rvm I deleted ruby:
rvm remove ruby
and lastly install ruby:
rvm install ruby
not sure if this step was required, but this is what I had in my console: Ruby was built without documentation, to build it run: rvm docs generate-ri
So I also ran this command. And after that I was finally able to sudo gem install sass.
Now it works!

Answer 2

Perform following steps in mac to install SASS error free
Install gpg
brew install -v gpg
Install gpg keys
gpg2 --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB
Allow curl to run without checking SSL (else command #4 will throw an error)
echo insecure >> ~/.curlrc
Install rvm
\curl -sSL -k https://get.rvm.io | bash
To use rvm, you will get an output after running command in #3 like:
To start using RVM you need to run source /Users/ymehta/.rvm/scripts/rvm
Copy paste command and hit Enter
Remove existing ruby version
rvm remove ruby
Install ruby
rvm install ruby
rvm docs generate-ri
Install sass
sudo gems install sass
Check sass version
sass --version
Same steps can be found at https://gist.github.com/Yashvi-Mehta/9ad81330d1703f12a00b63cf20c9cdb3