subr-x on older Emacsen

[Sebastian Wiesner]

Hello,

I’d like to use the new subr-x library in my Emacs Lisp projects, and I’m 
searching for advice on how to handle backwards compatibility.

As you know, subr-x was only recently introduced in Emacs trunk, and is not 
available in any Emacs release.  Currently, I simply copy those functions that 
I need into my code, guarding their definition with `(unless (features 'subr-x) 
…)'.

This scales poorly across many projects, obviously, so I’d like to know if 
there is a better approach to handle this problem.  Is their a compatibility 
package for subr-x on GNU ELPA, similar to cl-lib?

Greetings,
Sebastian Wiesner