compiler/comp_unit_interface.m:
When we cannot generate a .int0/.int/.int2 file because of file access
issues, the reason is *usually* that we can't read a .int3 file.
However, it is also possible that the reason is that we can't read
a .int0 file, so include that possibility in the overall error message.
(The "can't read this file" message, with the specifics of the file
that couldn't be read, would have been printed earlier.)
tests/invalid_make_int/missing_parent_import.int_err_exp:
tests/invalid_make_int/sub_c.int_err_exp:
tests/invalid_make_int/test_nested.int_err_exp:
Expect the updated error message.
bdabaf5dc9