Fix install command. Needs name of file in case building in a sandbox.

[CrazyCasta]

Building in a sandbox is common in many package systems. Install will often be installing into an empty folder. In this case install would create a file at say /usr/bin if CMD_DESTDIR were set to /usr, new version will create the /usr/bin directory and put the buildg file within the /usr/bin/buildg (the desired effect).

[ktock]

Thanks! Could you sign your commit? (i.e. Add Signed-off-by line to your commit message)

[CrazyCasta]

Done