Cygwin :: bcrypt-ruby - ERROR: Failed to build gem native extension

Question

When I try I install bcrypt-ruby gem I get the following error

I have Cygwin on Windows 7 32

$ gem install bcrypt-ruby
Building native extensions.  This could take a while...
ERROR:  Error installing bcrypt-ruby:
    ERROR: Failed to build gem native extension.

    /home/Bartek/.rvm/rubies/ruby-1.9.3-p194/bin/ruby.exe extconf.rb
creating Makefile

make
compiling bcrypt_ext.c
compiling crypt.c
compiling crypt_blowfish.c
compiling crypt_gensalt.c
compiling wrapper.c
In file included from wrapper.c:27:0:
/home/Bartek/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/backward/util.h:2:2:     warnin                                  g: #warning use "ruby/util.h" instead of bare         "util.h"
linking shared-object bcrypt_ext.so
bcrypt_ext.o:bcrypt_ext.c:(.text+0x29): undefined reference to `_ruby_bcrypt'
collect2: ld returned 1 exit status
Makefile:207: recipe for target `bcrypt_ext.so' failed
make: *** [bcrypt_ext.so] Error 1


Gem files will remain installed in /home/Bartek/.rvm/gems/ruby-1.9.3-        p194@ckdatabase/gems/bc                                  rypt-ruby-3.0.1 for inspection.
Results logged to /home/Bartek/.rvm/gems/ruby-1.9.3-p194@ckdatabase/gems/bcrypt-ruby-    3.0.1/e                                  xt/mri/gem_make.out

Anyone have an idea what to do with it? I've tried everything.

Answer 1

Copying the answer from the comments in order to remove this question from the "Unanswered" filter:

if we make rvm use system everything works fine

~ answer per Bartek S