minor changes in configure script

configure

@@ -16,12 +16,18 @@ help()
 {
   cat << EOF
 Configuration script for the fxengine library.
-This is actually very simple... ^^
+Usage: $0 [options...]
 
-Build option (there is just only one) :
+You should build out-of-tree by creating a build directory and configuring from
+there.
+
+
+Build option:
 
   --enable-profiling
+
      By default, profiling is disabled, tht means you will not have access to fps. :(
+
      This option enables fps count, but you need to have libprof (by Lephenixnoir) installed