Clean Install on Ubuntu Natty Fails

I've been having problems getting the Socket add-on to work on my Natty Ubuntu development machine. So I decided to see if it was just my configuration. I installed it on a *completely clean* install of Natty. Twice. And each time got this error.

Full steps:
1. Install Natty on Amazon EC2, with official Canonical Image (64bit)
2. SSH into instance and do:

$ sudo apt-get install cmake
(lots of packages installed, including the regular build stuff like gcc)
$ sudo apt-get install unzip
$ wget http://github.com/stevedekorte/io/zipball/master -O io-lang.zip
$ unzip -q io-lang.zip
$ cd stevedekorte-io-8cf3fec
$ mkdir build && cd build
$ cmake ..
cmake ..
-- The C compiler identification is GNU
-- The CXX compiler identification is GNU
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuration set to: DebugFast
-- Found AsyncRequest headers: /usr/include/aio.h
-- GMP libs: GMP_LIBRARIES-NOTFOUND GMPXX_LIBRARIES-NOTFOUND
-- Could NOT find GMP (missing:  GMP_INCLUDE_DIR GMP_LIBRARIES) 
-- checking for one of the modules 'libffi'
-- Could NOT find FFI (missing:  FFI_INCLUDE_DIRS FFI_LIBRARIES) 
-- checking for one of the modules 'cairo'
-- Could not find Cairo
-- checking for one of the modules 'glib-2.0'
-- checking for one of the modules 'cairo'
-- Could not find Cairo
-- Could NOT find Curses (missing:  CURSES_LIBRARY CURSES_INCLUDE_PATH) 
-- Found Fnmatch headers: /usr/include/fnmatch.h
-- Could NOT find Freetype (missing:  FREETYPE_LIBRARY FREETYPE_INCLUDE_DIRS) 
-- Could NOT find GLFW (missing:  GLFW_LIBRARY GLFW_INCLUDE_DIR) 
-- Could NOT find ZLIB (missing:  ZLIB_INCLUDE_DIR ZLIB_LIBRARY) 
-- Could NOT find PNG (missing:  PNG_LIBRARY PNG_PNG_INCLUDE_DIR) 
-- Could NOT find TIFF (missing:  TIFF_LIBRARY TIFF_INCLUDE_DIR) 
-- Could NOT find JPEG (missing:  JPEG_LIBRARY JPEG_INCLUDE_DIR) 
-- Found Iconv: /usr/lib/x86_64-linux-gnu/libc.so
-- Could NOT find LibXml2 (missing:  LIBXML2_LIBRARIES LIBXML2_INCLUDE_DIR) 
-- checking for one of the modules 'glib-2.0'
-- Could NOT find PythonLibs (missing:  PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS) 
-- Could NOT find PCRE (missing:  PCRE_INCLUDE_DIR PCRE_PCRE_LIBRARY PCRE_PCREPOSIX_LIBRARY) 
-- checking for one of the modules 'sqlite>=3;sqlite3'
-- Could not find Sqlite
-- Could NOT find OpenSSL (missing:  OPENSSL_LIBRARIES OPENSSL_INCLUDE_DIR) 
-- Found Syslog headers: /usr/include/syslog.h
-- Looking for include files CMAKE_HAVE_PTHREAD_H
-- Looking for include files CMAKE_HAVE_PTHREAD_H - found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE 
CMake Error at CMakeLists.txt:143 (string):
  string sub-command REGEX, mode REPLACE needs at least 6 arguments total to
  command.


-- rpmbuild binary not found, not building rpm package
-- Configuring incomplete, errors occurred!

--------------------

$ cmake --version
cmake version 2.8.3

Any ideas? Not that this addresses the issue with my Sockets not building (despite libevent being installed), but hey, small moves.

In general, I don't suppose there's any way of finding out what dependences the add-ons, or the whole of Io require?

Ian.