perl ".../config.h, needed by `Makefile'" not working after OSX Lion upgrade

SOLVED. See at bottom.

Just upgraded to OSX Lion and trying to get my Perl install running again:

sudo /usr/bin/perl -MCPAN -e 'install "MODULENAME"'

with any value of MODULENAME that I tried (e.g. JSON) produces:

...
Checking if your kit is complete...
Looks good
Writing Makefile for JSON
make: *** No rule to make target `/System/Library/Perl/5.12/darwin-thread-multi-2level/CORE/config.h', needed by `Makefile'.  Stop.
  MAKAMAKA/JSON-2.53.tar.gz
  /Developer/usr/bin/make -- NOT OK

I can't find anything resembling config.h anywhere, the directory exists though ...

Not even this works:

/usr/bin/cpan CPAN

SOLVED: Download and install latest version of XCode from AppStore. Note that just downloading XCode from AppStore does not install it (why, Apple, oh why?) but only dumps an installer into /Applications. Run the installer, which will fix this issue.

Solution

SOLVED: Download and install latest version of XCode from AppStore. Note that just downloading XCode from AppStore does not install it (why, Apple, oh why?) but only dumps an installer into /Applications. Run the installer, which will fix this issue.