title: Gem installation error: You have to install development tools first (Windows)
body: <p><strong>this question is for Windows</strong></p>
  <p>I tried installing the gem '<a href="https://github.com/simulacre/sinatra-websocket" rel="noreferrer">sinatra-websocket</a>', but when I ran <code>gem install sinatra-websocket</code>, I got this error...</p>
  <p><code>ERROR: Failed to build gem native extension</code></p>
  <p>... along with ...</p>
  <pre><code>C:/Ruby193/bin/ruby.exe extconf.rb
  checking for main() in -lc... *** 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.
  
  Provided configuration options:
      --with-opt-dir
      --without-opt-dir
      --with-opt-include
      --without-opt-include=${opt-dir}/include
      --with-opt-lib
      --without-opt-lib=${opt-dir}/lib
      --with-make-prog
      --without-make-prog
      --srcdir=.
      --curdir
      --ruby=C:/Ruby193/bin/ruby
      --with-thin_parser-dir
      --without-thin_parser-dir
      --with-thin_parser-include
      --without-thin_parser-include=${thin_parser-dir}/include
      --with-thin_parser-lib
      --without-thin_parser-lib=${thin_parser-dir}/lib
      --with-clib
      --without-clib
  C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:461:in `try_link0'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:476:in `try_link'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:619:in `try_func'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:845:in `block in have_library'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:254:in `open'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:254:in `open'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
      from C:/Ruby193/lib/ruby/1.9.1/mkmf.rb:840:in `have_library'
      from extconf.rb:4:in `&lt;main&gt;'
  </code></pre>
  <p>Here's what the <code>mkmf</code> file in <code>C:\Ruby193\lib\ruby\gems\1.9.1\gems\thin-1.6.3\ext\thin_parser</code> looks like:</p>
  <pre><code>&quot;gcc -o conftest -IC:/Ruby193/include/ruby-1.9.1/i386-mingw32 -IC:/Ruby193/include/ruby-1.9.1/ruby/backward -IC:/Ruby193/include/ruby-1.9.1 -I. -DFD_SETSIZE=2048  -DFD_SETSIZE=2048  -O3 -fno-omit-frame-pointer -g -Wall -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long -Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings -Wdeclaration-after-statement -Wimplicit-function-declaration conftest.c  -L. -LC:/Ruby193/lib -L.   -march=i486   -lmsvcrt-ruby191  -lshell32 -lws2_32 -limagehlp -lshlwapi  &quot;
  checked program was:
  /* begin */
  1: #include &quot;ruby.h&quot;
  2: 
  3: #include &lt;winsock2.h&gt;
  4: #include &lt;windows.h&gt;
  5: int main(int argc, char **argv)
  6: {
  7:   return 0;
  8: }
  /* end */
  </code></pre>
  <p>I'm using Windows 7.</p>
  <p>Why am I getting the error? There's a line stating &quot;could not create Makefile...&quot;, but is that relevant?</p>