One complication to be aware of is that .mod files are not just per-compiler, they are per-compiler-configuration.
Examples of things that can produce incompatibilities in .mod files:
- what option is in effect determining the KIND numbering system
- what option is in effect determining the precision/range of the default integer/real variables
- what option is in effect determining the level of runtime checking requested
Every compiler makes its own choices about .mod files.