Error installing gem 'scrapi'

tags ruby-on-rails ruby gem

I have installed Ruby 1.9.3 using the rubyinstaller.

I execute: gem install scrapi

I get the following:

Gem files will remain installed in C:/Ruby193/lib/ruby/gems/1.9.1/gems/ffi-1.0.1
1 for inspection.
Results logged to C:/Ruby193/lib/ruby/gems/1.9.1/gems/ffi-1.0.11/ext/ffi_c/gem_m
ake.out

The gem_make.out file contains the following ridiculous information:

C:/Ruby193/bin/ruby.exe extconf.rb
checking for ffi.h... no
checking for ffi.h in /usr/local/include... no
checking for rb_thread_blocking_region()... yes
checking for ruby_native_thread_p()... yes
checking for rb_thread_call_with_gvl()... yes
creating extconf.h
creating Makefile

make
libffi.gnu.mk:24: *** target pattern contains no `%'.  Stop.

Any ideas ?