Fixed bug #167

The configure script parses the value of $X_LIBS when looking at the
--enable-x11-shared, which is getting set on Ubuntu 5.10 to "-L/usr/X11R6/lib"
... however, Ubuntu stores all the Xlib stuff in /usr/lib.

The end result in SDL is that the dynamic X11 stuff gets disabled by default,
unless you override like this:

 ./configure --x-libraries=/usr/lib

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401573

configure.in

@@ -773,11 +773,15 @@ AC_HELP_STRING([--enable-x11-shared], [dynamically load X11 support [default=yes
                     x11ext_lib='libXext.so'
                     ;;
                 *)
-                    if test "x$X_LIBS" = "x"; then X_LIBS="-L/usr/lib"; fi
-                    x11_lib_spec=[`echo $X_LIBS | sed 's/.*-L\([^ ]*\).*/\1\/libX11.so.[0-9]/'`]
-                    x11_lib=`ls $x11_lib_spec 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`
-                    x11ext_lib_spec=[`echo $X_LIBS | sed 's/.*-L\([^ ]*\).*/\1\/libXext.so.[0-9]/'`]
-                    x11ext_lib=`ls $x11ext_lib_spec 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`
+                    x11_lib_spec=[`echo $X_LIBS | sed 's/.*-L\([^ ]*\).*/\1/'`]
+                    for path in $x11_lib_path /usr/lib /usr/X11/lib /usr/X11R6/lib
+                    do if test "x$x11_lib" = "x"; then
+                           x11_lib=[`ls $path/libX11.so.[0-9] 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`]
+                       fi
+                       if test "x$x11ext_lib" = "x"; then
+                           x11ext_lib=[`ls $path/libXext.so.[0-9] 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`]
+                       fi
+                    done
                     ;;
             esac