Microsoft Windows [Version 6.1.7600]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\Sergio>gem i date-performance
Building native extensions.  This could take a while...
ERROR:  Error installing date-performance:
        ERROR: Failed to build gem native extension.

C:/Ruby/bin/ruby.exe extconf.rb
creating Makefile

make
make: *** No rule to make target `/C/Ruby/include/ruby-1.9.1/ruby.h', needed by
`date_performance.o'.  Stop.


Gem files will remain installed in C:/Ruby/lib/ruby/gems/1.9.1/gems/date-perform
ance-0.4.8 for inspection.
Results logged to C:/Ruby/lib/ruby/gems/1.9.1/gems/date-performance-0.4.8/ext/ge
m_make.out

C:\Users\Sergio>make
make: *** No targets specified and no makefile found.  Stop.