php编译错误

qmailer

安装php5+apache2.2+Ras3.0
apache安装完毕

以下为编译过程

$ ./configure --prefix=/usr/local/php5
                   --with-apxs2=/usr/local/apache2/bin/apxs

configure: warning: You will need re2c 0.9.11 or later if you want to regenerate PHP parsers.
configure: warning: bison versions supported for regeneration of the Zend/PHP parsers: 1.28 1.35 1.75 1.875 2.0 2.1 (found: none).
checking for flex... lex
checking for yywrap in -ll... no
checking lex output file root... ./configure: line 3246: lex: command not found
configure: error: cannot find output from lex; giving up

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re2c是什么东东？
什么原因导致编译中止？

请各位大虾指教

achieverain

google  re2c 0.9.11 please

you will find the result