Do not use -D flag for install

[ryandesign]

The -D flag is a GNU extension not available on BSD install (e.g. on macOS).

See #56

Fixes:

install: illegal option -- D
usage: install [-bCcpSsv] [-B suffix] [-f flags] [-g group] [-m mode]
               [-o owner] file1 file2
       install [-bCcpSsv] [-B suffix] [-f flags] [-g group] [-m mode]
               [-o owner] file1 ... fileN directory
       install -d [-v] [-g group] [-m mode] [-o owner] directory ...

[SuperSandro2000]

What is the equivalent on bsd install to

-D create all leading components of DEST except the last, or all components of --target-directory, then copy SOURCE to DEST

?

[ryandesign]

Looks like it's -d:

     -d      Create directories.  Missing parent directories are created as required.

However -d means something else in GNU install. So there isn't a portable way to do this.

[rwos]

https://xkcd.com/927/

thanks, will merge! Still have that on my to do list, to steal a portable Makefile from some other project.

[ryandesign]

Er, I misread those manpages somewhat.

-d means the same thing in both BSD and GNU install: it means "create the named directory".

In GNU install, -D means "create any needed parent directories, then install the named file". BSD install doesn't have an equivalent of that.