Expand comment about building loaddefs.el.

1 files changed, 7 insertions, 4 deletions

diff --git a/lisp/Makefile.in b/lisp/Makefile.in
index a7ef180b18e..b8501c5021d 100644
--- a/lisp/Makefile.in
+++ b/lisp/Makefile.in
@@ -218,10 +218,13 @@ $(lisp)/progmodes/cc-mode.elc: \
 # Build loaddefs.el to make sure it's up-to-date.  If it's not, that
 # might lead to errors during the bootstrap because something fails to
 # autoload as expected.  If there is no emacs binary, then we can't
-# build autoloads yet.  In that case we have to use ldefs-boot.el;
-# bootstrap should always work with ldefs-boot.el.  (Because
-# loaddefs.el is an automatically generated file, we don't want to
-# store it in the source repository).
+# build autoloads yet.  In that case we have to use ldefs-boot.el.
+# Bootstrap should always work with ldefs-boot.el.  Therefore,
+# whenever a new autoload cookie gets added that is necessary during
+# bootstrapping, ldefs-boot.el should be updated by overwriting it with
+# an up-to-date copy of loaddefs.el that is uncorrupted by
+# local changes.  (Because loaddefs.el is an automatically generated
+# file, we don't want to store it in the source repository).
 
 bootstrap-prepare:
 	if test -x $(EMACS); then				\