I have never used Fortran under Code::Blocks (I used to code a lot of Fortran77 on VAX computers years ago). But I guess it is similar to C++ projects in this regard
Select your project, then use Project -> Build Options...
Under Compiler Settings you should have 3 tabs
Compiler options: See if your options are covered there first, if not go to "other options "
Other options: Here you can add additional compiler options, you could add "-ffree-line-length-none " or whatever here
#defines: Probably not for Fortran
This procedure is per project & build target. There is also a possibility to set it for all projects/build targets via Settings -> Compiler...