Compiling for x11: use `linker=lld`

`use_lld` boolean option has been replaced by `linker=<default|bfd|gold|lld|mold>`

development/compiling/compiling_for_x11.rst

@@ -225,7 +225,7 @@ the default GCC + GNU ld setup:
 To do so, install Clang and the ``lld`` package from your distribution's package manager
 then use the following SCons command::
 
-    scons platform=x11 use_llvm=yes use_lld=yes
+    scons platform=x11 use_llvm=yes linker=lld
 
 After the build is completed, a new binary with a ``.llvm`` suffix will be
 created in the ``bin/`` folder.