Why do I get these messages when compiling gnome-libs (and someothers too)?

[Michael Heldebrant <Heldebrant Michael mayo edu>]

What causes these to occur?
I'm running redhat 5.2 on alpha.

lots of things like this:

*** Warning: This library needs some functionality provided by -ldl.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have.

*** Warning: This library needs some functionality provided by -lXext.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have.

*** Warning: This library needs some functionality provided by -lX11.
*** I have the capability to make that library automatically link in when
*** you link to this library.  But I can only do this if you have a
*** shared version of the library, which you do not appear to have.

--mike