Since 97c43828fb the `file` package has
been part of stdenv, and no longer needs to be listed explicitly as a
build input. Let's remove the platform-specific inclusion for mingw64
as suggested by @mehmooda:
https://github.com/NixOS/nixpkgs/pull/168413#issuecomment-1147370500
I traced the line removed by this commit through the `git blame`; it
was initially added in this commit (and then shuffled around a few
dozen times by refactorings):
8b292a1b35
The commit message indicates that `libpng-1.6.20` was current at the
time. Although there are [libpng
archives](https://github.com/glennrp/libpng) available in git form,
the older versions don't have their autoconfery vendored in, so I
can't link to them. Fortunately the relevant bit hasn't changed since
then:
a37d483651/configure (L5575)
```
mingw* | pw32*)
# Base MSYS/MinGW do not provide the 'file' command needed by
# func_win32_libid shell function, so use a weaker test based on 'objdump',
# unless we find 'file', for example because we are cross-compiling.
if ( file / ) >/dev/null 2>&1; then
lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
lt_cv_file_magic_cmd='func_win32_libid'
else
# Keep this pattern in sync with the one in func_win32_libid.
lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
lt_cv_file_magic_cmd='$OBJDUMP -f'
fi
;;
```