Less 'make' chatter for VCSWITNESS

* Makefile.in (dirstate, VCSWITNESS): New macros.
(src): Use them to lessen 'make' chatter.

2 files changed, 10 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 0efa32aec55..9207bd5f104 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-01-04  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Less 'make' chatter for VCSWITNESS
+        * Makefile.in (dirstate, VCSWITNESS): New macros.
+        (src): Use them to lessen 'make' chatter.
+
 2015-01-01  Paul Eggert  <eggert@cs.ucla.edu>
 
         Fix copyright years by hand
diff --git a/Makefile.in b/Makefile.in
index b8d914b3bd7..7b271f12424 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -389,15 +389,13 @@ lib lib-src lisp nt: Makefile
 # repository pull. In git there is no single file that guarantees
 # this, but the local log for the current head should be close enough.
 #
-# Note the use of single quotes in the value of vcswitness.
-# This passes an unexpanded $srcdir to src's Makefile, which then
+# Pass an unexpanded $srcdir to src's Makefile, which then
 # expands it using its own value of srcdir (which points to the
 # source directory of src/).
+dirstate = .git/logs/HEAD
+VCSWITNESS = $(if $(wildcard $(srcdir)/$(dirstate)),$$(srcdir)/../$(dirstate))
 src: Makefile
-        dirstate='.git/logs/HEAD';                              \
-        vcswitness='$$(srcdir)/../'$$dirstate;                          \
-        [ -r "$(srcdir)/$$dirstate" ] || vcswitness='';                 \
-        $(MAKE) -C $@ all VCSWITNESS="$$vcswitness"
+        $(MAKE) -C $@ VCSWITNESS='$(VCSWITNESS)' all
 
 blessmail: Makefile src
         $(MAKE) -C lib-src maybe-blessmail