Most of the c89 arguments have corresponding parameters to the compiler, prelinker, and linkage editor. Therefore, if you specify fewer arguments to c89, a shorter parameter string is passed. For example, perhaps many -I options were specified, or absolute rather than relative names were used.
In the message text:
string1 is the step name.
Shorten the length of the arguments for the indicated step. Normally, you can accomplish this by removing one or more c89 options or operands. Alternatively, you may be able to use a more terse syntax, such as specifying relative instead of absolute pathnames.