--- Urlader/README	2012/01/08 09:12:52	1.3
+++ Urlader/README	2012/02/06 22:09:40	1.4
@@ -262,6 +262,54 @@
         <http://cvs.schmorp.de/deliantra/Deliantra-Client/util/>, but
         looking at them can lead to premature blindless.
 
+    Shared Libraries
+        It is often desirable to package shared libraries - for example the
+        Deliantra client packages SD>, Berkely DB, Pango and amny other
+        libraries that are unlikely to be available on the target system.
+
+        This usually requires some fiddling (see below), and additionally
+        some environment variables to be set.
+
+        For example, on ELF systems you usually want LD_LIBRARY_PATH=. and
+        on OS X, you want DYLD_LIBRARY_PATH=. (these are effectively the
+        default on windows).
+
+        These can most easily be specified when building the packfile:
+
+           urlader-util ... LD_LIBRARY_PATH=. ./perl run
+
+    Portability: RPATH
+        Often perl is linked against a shared libperl.so - and might be so
+        using an rpath. Perl extensikns likewise might use an rpath, which
+        means the binary will mostly ignore LD_LIBRARY_PATH, which leads to
+        trouble.
+
+        There is an utility called chrpath, whose -d option can remove the
+        rpath from binaries, shared library and shared objects.
+
+    Portability: OS X DLL HELL
+        OS X has the most severe form of DLL hell I have seen - if you link
+        against system libraries, which is practically unavoidable, you get
+        libraries of well-known names (e.g. libjpeg) that have nothing to do
+        with what you normally expect libjpeg to be, and there is no way to
+        get your version of libjpeg into your program.
+
+        Moreover, even if apple ships well-known libraries (e.g. libiconv),
+        they often ship patched versions which have a different ABI or even
+        API then the real releases.
+
+        The only way aorund this I found was to change all library names in
+        my releases (libjpeg.dylib becomes libdeliantra-jpeg.dylin and so
+        on), by patching the paths in the share dlibraries and shared
+        objects. install-name-tool (with -id and -change) works in many
+        cases, but often paths are embedded indirectly, so you might have to
+        use a *dirty* string replacement.
+
+SECURITY CONSIDERATIONS
+    The urlader executable itself does not support setuig/setgid operation,
+    or running with elevated privileges - it does no input sanitisation, and
+    is trivially exploitable.
+
 AUTHOR
      Marc Lehmann <schmorp@schmorp.de>
      http://home.schmorp.de/