Gem::Ext::BuildError: ERROR: Failed to build gem native extension - ruby

Question

I am trying bundle install in my windows env and it fails with the below error.
I did install dev kit:
ruby dk.rb init
ruby dk.rb install
When running bundle install, I get the following output.
DL is deprecated, please use Fiddle
Fetching gem metadata from https://rubygems.org/.........
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...
Using mime-types 2.3
Using mini_portile 0.6.0
Using nokogiri 1.6.2.1
Using rack 1.5.2
Using rack-test 0.6.2
Using xpath 2.0.0
Using capybara 2.3.0
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
c:/Ruby200/bin/ruby.exe extconf.rb
creating Makefile
make "DESTDIR=" clean
0 [main] rm 10376 open_stackdumpfile: Dumping stack trace to rm.exe.stackdump
make: [clean-static] Error 5 (ignored)
0 [main] rm 14216 open_stackdumpfile: Dumping stack trace to rm.exe.stackdump
make: [clean] Error 5 (ignored)
make "DESTDIR="
generating generator-i386-mingw32.def
compiling generator.c
In file included from c:/Ruby200/include/ruby-2.0.0/ruby.h:33:0,
from ../fbuffer/fbuffer.h:5,
from generator.c:1:
c:/Ruby200/include/ruby-2.0.0/ruby/ruby.h:125:14: error: size of array 'ruby_check_sizeof_voidp' is negative
In file included from c:/Ruby200/include/ruby-2.0.0/ruby.h:33:0,
from ../fbuffer/fbuffer.h:5,
from generator.c:1:

Answer 1

I got a similar error when running bundle and it was fixed by agreeing to the Xcode license. I had recently updated Xcode and it turns out that I needed to re-agree to the license in order to use the command line tools successfully.
Just run
xcodebuild -license

Answer 2

Mine was also an xcode issue and I'm using a Mac. I had to use sudo though to give permission via the shell.
sudo xcodebuild -license
This worked for me.