master 2416790: Add a note about testing out-of-tree builds

[Robert Pluim]

branch: master
commit 24167905955ed6d2aa9d474c80402a40c1cc7b92
Author: Robert Pluim <rpluim@gmail.com>
Commit: Robert Pluim <rpluim@gmail.com>

    Add a note about testing out-of-tree builds
    
    * CONTRIBUTE: Ask contributors to test out-of-tree builds when
    making build system changes.
---
 CONTRIBUTE | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/CONTRIBUTE b/CONTRIBUTE
index 2d70c49..023d026 100644
--- a/CONTRIBUTE
+++ b/CONTRIBUTE
@@ -157,6 +157,14 @@ top-level directory.  Most tests are in the directory 
"test/".  From
 the "test/" directory, run "make <filename>" to run the tests for
 <filename>.el(c).  See "test/README" for more information.
 
+If you're making changes that involve the Emacs build system, please
+test 'out-of-tree' builds as well, i.e.:
+
+    mkdir emacs-build
+    cd emacs-build
+    ../path-to-emacs-sources/configure
+    make
+
 ** Commit messages
 
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