Please don't. Running random scripts from the internets to install stuff is a idiotic idea that deserves to die already.

Make your build process dumb and installation process even dumber. The former should just run the compiler (as opposed to downloading and installing semi-related stuff; this belongs elsewhere), and the latter should just copy files. This way somebody could easily make a tarball or RPM/DEB package, which allows for repeatable installations. Running sh&t from the internets doesn't allow to reliably build packages and install software.

Don't assume that your users are idiots who cannot run two or three commands in terminal.