Cant find some of source make files

These make files needed for add character set now i cant find it
I have generic source distribution and with cmake generated and compiled but i cant see these files

strings/Makefile.am
libmysql/Makefile.shared

am i did something wrong?

here is add character set in doc
MySQL :: MySQL 5.5 Reference Manual :: 9.3 Adding a New Character Set

i use source distribution version 5.5.11

Please answer my question Thanks