Fortran: Do not suppress explicit use of implicit include directories
Since !2855 (merged) we actually populate
CMAKE_Fortran_IMPLICIT_INCLUDE_DIRECTORIES for the first time. This
value may be useful to project code to pass to other tooling that wants
to preprocess the way Fortran does, so we should compute the value.
However, compilers like
gfortran do not actually search their own
implicit include directories for
.mod files. The directories must be
-I in order for
.mod files in them to be found.
Since Fortran has no standard library header files that we need to avoid
overriding, it is safe to not filter out implicit include directories
from those passed explicitly via
-I options. Skip this filtering so
that include directories specified by project code to find
will be searched by the compiler even if they happen to be implicitly
searched by the preprocessor.
Fixes: #18914 (closed)