homebrew install postgresql problem - macos

Question

I'm new to OSX and want to install postgresql, as it is my preferred db for django.
I installed xcode and can start it, which is a prerequisite for homebrew.
Then I installed homebrew and run brew install postgresql, getting the following warning and errors. First of all I get an Xcode is not installed warning, whereas it is definitely installed. I think the reason for this warning is described in this post: https://github.com/mxcl/homebrew/issues/2567
Below the traceback.
TK$ brew install postgresql
Warning: Xcode is not installed! Builds may fail!
==> Downloading ftp://ftp.cwru.edu/pub/bash/readline-6.1.tar.gz
File already downloaded and cached to /Users/TK/Library/Caches/Homebrew
==> Downloading patches
######################################################################## 100.0%
######################################################################## 100.0%
==> Patching
patching file complete.c
patching file patchlevel
patching file readline.h
patching file patchlevel
==> ./configure --prefix=/usr/local/Cellar/readline/6.1 --mandir=/usr/local/Cell
checking build system type... i386-apple-darwin10.7.3
checking host system type... i386-apple-darwin10.7.3
Beginning configuration for readline-6.1 for i386-apple-darwin10.7.3
checking whether make sets $(MAKE)... no
checking for gcc... /usr/bin/cc
checking for C compiler default output file name...
configure: error: in `/private/tmp/homebrew-readline-6.1-3bbC/readline-6.1':
configure: error: C compiler cannot create executables
See `config.log' for more details.
==> Exit Status: 77
http://github.com/mxcl/homebrew/blob/master/Library/Formula/readline.rb#L24
==> Environment
/usr/local/Library/Homebrew/utils.rb:275:in `llvm_build_version': undefined method `/' for "/Developer":String (NoMethodError)
from /usr/local/Library/Homebrew/cmd/--config.rb:9:in `llvm'
from /usr/local/Library/Homebrew/cmd/--config.rb:61:in `config_s'
from /usr/local/bin/brew:116
If i run brew-config I get the following trackeback.
TK$ brew --config
Error: undefined method `/' for "/Developer":String
Please report this bug: https://github.com/mxcl/homebrew/wiki/new-issue
/usr/local/Library/Homebrew/utils.rb:275:in `llvm_build_version'
/usr/local/Library/Homebrew/cmd/--config.rb:9:in `llvm'
/usr/local/Library/Homebrew/cmd/--config.rb:61:in `config_s'
/usr/local/Library/Homebrew/cmd/--config.rb:5:in `__config'
/usr/local/bin/brew:82:in `send'
/usr/local/bin/brew:82
Any idea what I did wrong?

Answer 1

configure: error: C compiler cannot create executables
and
Error: undefined method `/' for "/Developer":String
suggest that you do not have Xcode and gnu c++ installed. Install code from your OS disk or register as a developer (free) and get XCode 3 or buy Xcode from AppStore,