use time of last git commit for version time

diff --git a/autogen.sh b/autogen.sh
index 27db14172b3764659e870a9d62ed30bc917cc53d..764823cae0175f96a3163b435d23ec6d6270e96c 100755 (executable)
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,7 +1,14 @@
 #! /bin/sh
 
-# Use "now" if we can't get time of last commit
-GRAPHVIZ_VERSION_DATE=$( date -u +%Y%m%d.%H%M )
+GRAPHVIZ_VERSION_DATE=$( git log -n 1 --format=%ct )
+if test $? -eq 0; then
+    GRAPHVIZ_VERSION_DATE=$( date -u +%Y%m%d.%H%M -d @$GRAPHVIZ_VERSION_DATE )
+    echo "Version date is based on time of last commit: $GRAPHVIZ_VERSION_DATE"
+else
+    GRAPHVIZ_VERSION_DATE=$( date -u +%Y%m%d.%H%M )
+    echo "Warning: we do not appear to be running in a git clone."
+    echo "Version date is based on time now: $GRAPHVIZ_VERSION_DATE"
+fi
 
 # initialize version for a "stable" build
 cat >./version.m4 <<EOF