Merge bitcoin/bitcoin#25359: doc: add distcc to productivity notes

14093d5 doc: add distcc to productivity notes (Sjors Provoost)

Pull request description:

  If you have more than one computer at your disposal, you can use [distcc](https://www.distcc.org) to speed up compilation.

ACKs for top commit:
  laanwj:
    ACK 14093d5
  brunoerg:
    ACK 14093d5
  w0xlt:
    ACK bitcoin/bitcoin@14093d5

Tree-SHA512: 2c436bdea5ab750330055778eb5817361d16b046f219d53692577439e2fd8403febf78ac8e8b20ed158c650c76252b50cfc91f4ec8375cdd522cc408068d547b

Author: laanwj

doc/productivity.md

@@ -9,6 +9,7 @@ Table of Contents
    * [Disable features with `./configure`](#disable-features-with-configure)
    * [Make use of your threads with `make -j`](#make-use-of-your-threads-with-make--j)
    * [Only build what you need](#only-build-what-you-need)
+   * [Compile on multiple machines](#compile-on-multiple-machines)
    * [Multiple working directories with `git worktrees`](#multiple-working-directories-with-git-worktrees)
    * [Interactive "dummy rebases" for fixups and execs with `git merge-base`](#interactive-dummy-rebases-for-fixups-and-execs-with-git-merge-base)
 * [Writing code](#writing-code)
@@ -81,6 +82,10 @@ make -C src bitcoin_bench
 
 (You can and should combine this with `-j`, as above, for a parallel build.)
 
+### Compile on multiple machines
+
+If you have more than one computer at your disposal, you can use [distcc](https://www.distcc.org) to speed up compilation. This is easiest when all computers run the same operating system and compiler version.
+
 ### Multiple working directories with `git worktrees`
 
 If you work with multiple branches or multiple copies of the repository, you should try `git worktrees`.