C:\Users\Patryk>gem install bcrypt
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing bcrypt:
        ERROR: Failed to build gem native extension.

    C:/Ruby200/bin/ruby.exe extconf.rb
checking for ruby/util.h... yes
creating Makefile

make "DESTDIR=" clean
process_begin: CreateProcess(NULL, rm -f, ...) failed.
make (e=2): Nie mo┐na odnalečŠ okreťlonego pliku.

make: [clean-static] B│╣d 2 (zignorowany)
process_begin: CreateProcess(NULL, rm -f bcrypt_ext.so *.o *.bak mkmf.log bcrypt_ext-i386-mingw32.def .*.time, ...) failed.
make (e=2): Nie mo┐na odnalečŠ okreťlonego pliku.

make: [clean] B│╣d 2 (zignorowany)

make "DESTDIR="
generating bcrypt_ext-i386-mingw32.def
System nie może odnaleźć określonej ścieżki.
make: *** [bcrypt_ext-i386-mingw32.def] B│╣d 1

make failed, exit code 2

Gem files will remain installed in C:/Ruby200/lib/ruby/gems/2.0.0/gems/bcrypt-3.1.7 for inspection.
Results logged to C:/Ruby200/lib/ruby/gems/2.0.0/extensions/x86-mingw32/2.0.0/bcrypt-3.1.7/gem_make.out