configure: add help

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/configure b/configure
index 09e985e..9273449 100755
--- a/configure
+++ b/configure
@@ -115,6 +115,11 @@
   --enable-gfio)
     gfio="yes"
     ;;
+  --help)
+    echo "--cc=                  Specify compiler to use"
+    echo "--enable-gfio          Enable building of gtk gfio"
+    exit 0
+    ;;
   *)
   echo "Bad option $opt"
   exit 1