Gem Install Problems... It seems like the problem is in 1.9.3-p125

gistfile1.md

#$ gem install couchbase --pre#

...
/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/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 /Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:491:in `block in try_compile'
	from /Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:443:in `with_werror'
	from /Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:491:in `try_compile'
	from extconf.rb:89:in `<main>'

#$ cat mkmf.log#

"/usr/bin/gcc-4.2 -o conftest -I/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/x86_64-darwin11.3.0 
-I/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1/ruby/backward 
-I/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/include/ruby-1.9.1 -I. 
-I/usr/local/opt/libevent/include 
-I/usr/local/include -I/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/include 
-I/usr/include -I/Users/jasdeep/.rvm/usr/include 
-D_XOPEN_SOURCE 
-D_DARWIN_C_SOURCE    
-O3 -g -Wextra -Wno-unused-parameter -Wno-parentheses -Wno-long-long 
-Wno-missing-field-initializers -Wpointer-arith -Wwrite-strings 
-Wdeclaration-after-statement -Wshorten-64-to-32 -Wimplicit-function-declaration  
-fno-common -pipe  -std=c99 -Wall -Wextra  conftest.c  -L. 
-L/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/lib -L/usr/local/opt/libevent/lib -L/usr/local/lib 
-L/Users/jasdeep/.rvm/rubies/ruby-1.9.3-p125/lib 
-L/usr/lib 
-L/Users/jasdeep/.rvm/usr/lib -L. 
-L/usr/local/lib      
-lruby.1.9.1  -lpthread -ldl -lobjc  "
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main() {return 0;}
/* end */

Y u no install development tools or xcode