http://gcc.gnu.org/ml/fortran/2008-06/msg00048.html
For the sake of completeness, I want to flag that with recent snapshots of GFortran, on CYGWIN, there are the following warnings, also with a simple test-case: $ cat hello.F95 program hello print *,'Hello World!' end program hello $ gfortran hello.F95 f951: warning: command line option "-idirafter" is valid for C/C++/ObjC/ObjC++ but not for Fortran -- Summary: preprocessing: option -idirafter undefined for fortran Product: gcc Version: 4.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran AssignedTo: dfranke at gcc dot gnu dot org ReportedBy: dfranke at gcc dot gnu dot org GCC host triplet: cygwin http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36457