PHP6 build help

Ubuntu Breezy Badger, AMD 64 I am trying to build PHP6 from source. I must admit to being a novice at *nix systems, but I am learning - so please be gentle. :) I have already gotten a copy of the PHP6 source from CVS, downloaded the autoconf version 2.13 as well as the ICU and ran the ./buildconf. But when I tried to do the ./configure, I received back an error message that I do not understand. Can someone please explain what has happened and point me in a general direction on what I need to do to get the ./configure to work. (Sorry for such a general question) last set of output: lig@lig-laptop:/usr/local/php6$ sudo ./configure creating cache ./config.cache checking for Cygwin environment... no checking for mingw32 environment... no checking for egrep... grep -E checking for a sed that does not truncate output... /bin/sed checking host system type... x86_64-unknown-linux-gnu checking target system type... x86_64-unknown-linux-gnu checking for gcc... gcc checking whether the C compiler (gcc ) works... yes checking whether the C compiler (gcc ) is a cross-compiler... no checking whether we are using GNU C... yes checking whether gcc accepts -g... yes checking whether gcc and cc understand -c and -o together... yes checking how to run the C preprocessor... gcc -E checking for AIX... no checking whether ln -s works... yes checking if compiler supports -R... no checking if compiler supports -Wl,-rpath,... yes checking for re2c... no configure: warning: You will need re2c 0.9.11 or later if you want to regenerate PHP parsers. checking for gawk... no checking for nawk... nawk checking if nawk is broken... no checking for bison... no checking for byacc... no checking for bison version... invalid configure: warning: bison versions supported for regeneration of the Zend/PHP parsers: 1.28 1.35 1.75 1.875 2.0 2.1 2.2 (found: none). checking for flex... lex checking for yywrap in -ll... no checking lex output file root... ./configure: line 3210: lex: command not found configure: error: cannot find output from lex; giving up -- life is a game... so have fun.