I have an error when compilate with compass gulp

I used to use compass with gulp to check my scss files and compile it to a css file on Mac OSX.

For some reasons that i don't know and don't understand, it doesn't work anymore.

I have this error :

events.js:136
throw er; // Unhandled 'error' event
^

Error: spawn /usr/local/bin/compass ENOENT
at _errnoException (util.js:1031:13)
at Process.ChildProcess._handle.onexit (internal/child_process.js:201:19)
at onErrorNT (internal/child_process.js:389:16)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickCallback (internal/process/next_tick.js:180:9)

After checking how to fix this error, i try to execute this :

sudo gem install -n /usr/local/bin compass

But i have 2 more errors when executing this :

Building native extensions. This could take a while...
ERROR:  Error installing compass:
    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 ./siteconf20181212-27008-jvtxi1.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.

and

/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-16/2.3.0/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-16/2.3.0/ffi-1.9.25/gem_make.out

In the /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-16/2.3.0/ffi-1.9.25/mkmf.log file, i have this :

package configuration for libffi is not found
"xcrun clang -o conftest -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/ruby-2.3.0/universal-darwin16 -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/include/ruby-2.3.0/ruby/backward -I/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/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 -iwithsysroot /usr/local/libressl/include conftest.c  -L. -L/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib -L.             -L /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.Internal.sdk/usr/local/libressl/lib -L/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.Internal.sdk/usr/local/lib   -arch x86_64 -arch i386   -lruby.2.3.0  -lpthread -ldl -lobjc "
In file included from conftest.c:1:
In file included from 

/Library/Developer/ CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Ruby.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: 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 */

Do you have any ideas that could help me to fix that and can let me use compass + gulp again ?