Fix: add wait when linking library with *.resp file

[zoziha]

Description

Fix #807 .

Linking the link library takes a while, the *.resp file is occupied, if fpm delete the resp file without waiting for linking to complete, we will get an error, this PR intends to fix it.

• Remove OMP critical;
• Add wait for linking.
• Use local delete_file_win32.

[awvwgk]

Looks good to me.

[LKedward]

Thanks @zoziha, however I'm a little confused. I thought the default for execute_command_line was to be synchronous if wait isn't present, so adding wait=.true. shouldn't change the existing behaviour should it? Or have a misunderstood?

[zoziha]

@LKedward , I agree with your point of view, I think this PR has no substantial progress, it is recommended to close. Sorry that I was wrong.

The cause of Fortran runtime error: File cannot be deleted is still unknown at present, this error still occurs at a very very low frequency, should we consider adding iostat for the close in delete_file? Turn it into a warning.
(It might even be possible to ignore this error since it's not actually a compilation error, or add extra way to delete the resp file?)

[LKedward]

No need to apologise! I appreciate you looking into this issue @zoziha , I have also noticed it still cropping up sporadically (though less frequently than before).

... should we consider adding iostat for the close in delete_file? Turn it into a warning.

This seems like it would be a good idea! We just need to be careful that other parts of fpm don't rely on delete_file always working, though I don't think that is the case.

Another option could be to use iostat to retry the delete operation 1 or 2 times - I suggest this since I suspect the underlying issue could be with the Windows OS and not with anything in our code.

[zoziha]

Thanks for the reply @LKedward , I think this is a known problem on Windows, we should probably do additional processing based on the iostat value of close: ignore it (fpm will try to delete resp file again the next time it builds the code), continue to try to delete, or change the deletion method, etc. .
We can choose a method we think is appropriate to deal with it.

@awvwgk , do you have any good suggestions for this?

[zoziha]

I returns iostat in the delete_file, but do not process iostat, so the consequence is that resp has a probability not been removed. It may be replaced in a later fpm build.

I tried to delete the resp file one more time according to iostat, but the effect was that resp was still not deleted. This is what I can be sure of.

The extra way is to add a subroutine that calls the shell's rm program to remove the resp file, but it may not be very necessary.

[awvwgk]

Is this patch ready to go?

[zoziha]

Since #807 only happens on Windows OS, I think it might be a good decision to use preprocessing to declare a unique delete_file_win32 only for Windows.

By the way, I think this PR has nothing more to submit, it is ready to go.