리눅스에 apm설치시..

아래와 같은 오류가 드네요 어떡하죠???

php 설치시에 이럽니다..

[root@localhost php4]# ./configure --with-mysql=/usr/local/mysql --with-apache=/usr/local/apache --enable-track-vars=yes
creating cache ./config.cache
checking host system type... i686-pc-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 if compiler supports -R... no
checking if compiler supports -Wl,-rpath,... yes
checking for re2c... exit 0;
checking for ranlib... ranlib
checking whether ln -s works... yes
checking for mawk... no
checking for gawk... gawk
checking for bison... no
checking for byacc... no
configure: warning: You will need bison if you want to regenerate the PHP parsers.
checking for flex... lex
checking for yywrap in -ll... no
checking lex output file root... ./configure: line 2425: lex: command not found
configure: error: cannot find output from lex; giving up
[root@localhost php4]# cd ..