tools/configure.sh: Don't distclean if no config was already in place.

tools/configure.sh

@@ -40,7 +40,7 @@ USAGE="
 USAGE: ${0} [-E] [-e] [-l|m|c|u|g|n] [-a <app-dir>] <board-name>:<config-name> [make-opts]
 
 Where:
-  -E enforces distclean.
+  -E enforces distclean if already configured.
   -e performs distclean if configuration changed.
   -l selects the Linux (l) host environment.
   -m selects the macOS (m) host environment.
@@ -171,11 +171,10 @@ if [ ! -r ${src_config} ]; then
   exit 5
 fi
 
-if [ "X${enforce_distclean}" = "Xy" ]; then
-  make -C ${TOPDIR} distclean $*
-fi
-
 if [ -r ${dest_config} ]; then
+  if [ "X${enforce_distclean}" = "Xy" ]; then
+    make -C ${TOPDIR} distclean $*
+  else
     if cmp -s ${src_config} ${backup_config}; then
       echo "No configuration change."
       exit 0
@@ -188,6 +187,7 @@ if [ -r ${dest_config} ]; then
       echo "Do 'make distclean' and try again."
       exit 6
     fi
+  fi
 fi
 
 # Extract values needed from the defconfig file.  We need: