Hello,

While Emacs correctly picks makefile-gmake-mode when visiting a file
with the following shebang:

  #!/usr/bin/make -f

It fails to do so for this shebang:

  #!/usr/bin/env -S make -f

env(1) suggests -S is the idiomatic way to pass arguments to programs in
shebangs:

>    -S/--split-string usage in scripts
>        The -S option allows specifying multiple parameters in a script.
>        Running a script named 1.pl containing the following first line:
> 
>               #!/usr/bin/env -S perl -w -T
>               ...
> 
>        Will execute perl -w -T 1.pl .
> 
>        Without the '-S' parameter the script will likely fail with:
> 
>               /usr/bin/env: 'perl -w -T': No such file or directory

I've poked at lisp/files.el; the attached diff seems sufficient to make
Emacs pick makefile-gmake-mode .