save a script on how this build was done

gtk/build.sh

@@ -33,6 +33,17 @@ if [ $# -gt 0 ]; then
     eval "$*"
 fi
 
+# note how we were run
+now_time=$(date +%H_%M_%S)
+now=$(date)
+cat <<EOF > build_run.$now_time.sh
+#!/bin/bash
+# Auto generated by $0
+# Run by $USER at $now
+# INITIAL_DIR=$INITIAL_DIR
+$0 $*
+EOF
+
 # we save some config for sub-processes
 build_save_execution_config