title: Ruby 1.9.2 and pcap gem? Compiling error
body: <p>I am having trouble installing the pcap gem with ruby 1.9.2... It works fine with 1.8.7. Anyone know whats going on?</p>
  
  <pre><code>wuntee@wuntee:~$ rvm use system
  Now using system ruby.
  wuntee@wuntee:~$ ruby -v
  ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]
  wuntee@wuntee:~$ gem install pcap
  WARNING:  Installing to ~/.gem since /Library/Ruby/Gems/1.8 and
        /usr/bin aren't both writable.
  WARNING:  You don't have /Users/wuntee/.gem/ruby/1.8/bin in your PATH,
        gem executables will not run.
  Building native extensions.  This could take a while...
  Successfully installed pcap-0.7.0
  1 gem installed
  Installing ri documentation for pcap-0.7.0...
  Installing RDoc documentation for pcap-0.7.0...
  wuntee@wuntee:~$ rvm use 1.9.2
  Using /Users/wuntee/.rvm/gems/ruby-1.9.2-p180
  wuntee@wuntee:~$ ruby -v
  ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-darwin10.6.0]
  wuntee@wuntee:~$ gem install pcap
  Building native extensions.  This could take a while...
  ERROR:  Error installing pcap:
      ERROR: Failed to build gem native extension.
  
          /Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/bin/ruby extconf.rb
  checking for socket() in -lsocket... no
  checking for gethostbyname() in -lxnet... no
  checking for hstrerror()... yes
  checking for pcap.h... yes
  checking for pcap_open_live() in -lpcap... yes
  checking for pcap_compile_nopcap()... yes
  creating Makefile
  
  make
  gcc -I. -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -DHAVE_HSTRERROR -DHAVE_PCAP_H -DHAVE_PCAP_COMPILE_NOPCAP -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -I/usr/local/include  -o icmp_packet.o -c icmp_packet.c
  gcc -I. -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/x86_64-darwin10.6.0 -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1/ruby/backward -I/Users/wuntee/.rvm/rubies/ruby-1.9.2-p180/include/ruby-1.9.1 -I. -DHAVE_HSTRERROR -DHAVE_PCAP_H -DHAVE_PCAP_COMPILE_NOPCAP -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE   -fno-common -I/usr/local/include  -o ip_packet.o -c ip_packet.c
  ip_packet.c: In function ‘ipp_set_src’:
  ip_packet.c:117: error: ‘struct RString’ has no member named ‘ptr’
  ip_packet.c: In function ‘ipp_set_dst’:
  ip_packet.c:118: error: ‘struct RString’ has no member named ‘ptr’
  ip_packet.c: In function ‘new_ipaddr’:
  ip_packet.c:186: warning: cast to pointer from integer of different size
  ip_packet.c: In function ‘ipaddr_s_new’:
  ip_packet.c:203: error: ‘struct RString’ has no member named ‘ptr’
  ip_packet.c:213: warning: format not a string literal and no format arguments
  ip_packet.c: In function ‘ipaddr_s_load’:
  ip_packet.c:320: error: ‘struct RString’ has no member named ‘len’
  ip_packet.c:324: error: ‘struct RString’ has no member named ‘ptr’
  make: *** [ip_packet.o] Error 1
  
  
  Gem files will remain installed in /Users/wuntee/.rvm/gems/ruby-1.9.2-p180/gems/pcap-0.7.0 for inspection.
  Results logged to /Users/wuntee/.rvm/gems/ruby-1.9.2-p180/gems/pcap-0.7.0/ext/gem_make.out
  wuntee@wuntee:~$ 
  </code></pre>