11626 introduce /etc/versions/build
11627 clean up UUID code for ::status

@@ -133,10 +133,13 @@
 
 # POST_NIGHTLY can be any command to be run at the end of nightly.  See
 # nightly(1) for interactions between environment variables and this command.
 #POST_NIGHTLY=
 
+# Populates /etc/versions/build on each nightly run
+export BUILDVERSION_EXEC="git describe --all --long --dirty"
+
 # -----------------------------------------------------------------------------
 # You are less likely to need to modify parameters below.
 # -----------------------------------------------------------------------------
 
 # Maximum number of dmake jobs.  The recommended number is 2 + NCPUS,