I put a printf statement in the "main.c" code and built it. Later when I tried to execute INITDB, I got the following error
The program "postgres" was found by xxxx but was not the same version as initdb.Check your installation
After some analysis, I figured out that this error is being generated because "ret" code from "PG_CTL.c" is returning a non zero return code while it is comparing the line and versionstr in "exec.c". It looks like while reading the line in "pipe_read_line" method, it is concatenating the printf statement with the postgres version(postgres (PostgreSQL)xxxxx).
I thought this probably is a defect and maybe the buffer needs to be flushed out before reading it in "pipe_read_line" method. Before doing further investigation and putting a possible fix, I thought to check with this group if it is worth putting the effort.