Using chmod fails under MinGW

[Brian Dessent]

Arjen Markus wrote:

> I still think there is a problem with gfortran wrt chmod(): if it uses
> an external utility to do the job, then linking the program should
> work, even if it does not actually change the file permissions
> because there is no such external utility available. It is, however,
> in the link phase that the problem occurs.

The real problem is that the current implementatin of chmod in
libgfortran is hardcoded to use fork() and exec() to invoke the external
/bin/chmod, rather than system().  MinGW has no fork() nor is "/bin"
likely to be meaningful there, so the implementation would need a
rewrite in order to even compile for MinGW, let alone the problem of no
external chmod binary likely to be available in the first place.

Brian