Source lines longer than the applicable length are truncated to that
length.
Currently, g77 does not warn if the truncated characters are
not spaces, to accommodate existing code written for systems that
treated truncated text as commentary (especially in columns 73 through 80).
See Options Controlling Fortran Dialect,
for information on the -ffixed-line-length-n option,
which can be used to set the line length applicable to fixed-form
source files.