deps: create empty file instead of dummy file.

This change is per an automake thread, see both before and after:
https://lists.gnu.org/archive/html/automake/2022-05/msg00006.html

* lib/am/depend.am ($(am__depfiles_remade)): create empty files
for dependencies instead of files with a line '# dummy'. Turns out
this is noticeably faster.
* THANKS: update Jan's email address.
* NEWS: mention this.

diff --git a/NEWS b/NEWS
index 8a1cbed49036db9fb1ea296d0b384886339f76b6..3a9ede1a6e01d4db2085864e3164bd69009aa6e4 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -25,6 +25,8 @@ New in 1.17:
   - Generated file timestamp checks now handle filesystems with sub-second
     timestamp granularity dynamically.
 
+  - Dependency files are now empty, instead of '# dummy', for speed.
+
   - Systems with non-POSIX "rm -f" behavior are now supported, and intent to
     drop support for them has been reversed.  The ACCEPT_INFERIOR_RM_PROGRAM
     setting no longer exists.

diff --git a/THANKS b/THANKS
index 41e15eb73b34470315c0ba74794ffe874b8d5bcf..f2f3188ce1a13d65ca9619dc8ecdd81138acee5e 100644 (file)
--- a/THANKS
+++ b/THANKS
@@ -177,7 +177,7 @@ James Bostock                   james.bostock@gmail.com
 James Henstridge                james@daa.com.au
 James R. Van Zandt              jrv@vanzandt.mv.com
 James Youngman                  jay@gnu.org
-Jan Engelhardt                  jengelh@medozas.de
+Jan Engelhardt                  jengelh@inai.de
 Janos Farkas                    chexum@shadow.banki.hu
 Jared Davis                     abiword@aiksaurus.com
 Jason DeVinney                  jasondevinney@gmail.com

diff --git a/lib/am/depend.am b/lib/am/depend.am
index ecc6180a6da5cac9996474fdcf46b0eebddf791c..ecea1fcaa9bcdd44d185ed39409660caaafa3be2 100644 (file)
--- a/lib/am/depend.am
+++ b/lib/am/depend.am
@@ -18,7 +18,9 @@ am__mv = mv -f
 
 $(am__depfiles_remade):
        @$(MKDIR_P) $(@D)
-       @echo '# dummy' >$@-t && $(am__mv) $@-t $@
+       @: >>$@
+## It's faster to create an empty file, hence :. See thread before and after
+## https://lists.gnu.org/archive/html/automake/2022-05/msg00006.html.
 
 am--depfiles: $(am__depfiles_remade)
 .PHONY: am--depfiles