build-sys: bail out if we need to regenerate a linker script but have no ctags.

diff --git a/build-aux/gen-linker-script b/build-aux/gen-linker-script
index bb322b4..3a41950 100755 (executable)
--- a/build-aux/gen-linker-script
+++ b/build-aux/gen-linker-script
@@ -100,6 +100,13 @@ else
     ignore_opts=""
 fi
 
+# check that we have ctags
+which ctags >& /dev/null
+if [ "$?" != "0" ]; then
+    error "Needs ctags to regenerate linker script $OUTPUT..."
+    exit 1
+fi
+
 # generate the output
 [ -n "$QUIET" ] || info "Generating linker script $OUTPUT..."
 rm -f $OUTPUT