Added more info about removing lib info.

Documentation/source/advanced_config.rst

@@ -217,7 +217,19 @@ the application only needs to specify the name of the libraries required, e.g.:
 
     link_exe(state, libs=["yaxt", "xios"])
 
-The linker will then use the specified linking options.
+The linker will then use the specified options. Library definitions can
+also be removed:
+
+.. code-block::
+    :linenos:
+
+        tr = ToolRepository()
+        linker = tr.get_tool(Category.LINKER, "linker-ifort")
+
+        linker.remove_lib_flags("yaxt")
+
+Note that if a linker has no information for the specified library name, i.e.
+the definition was never added, no error will be raised when removing it.
 
 A linker object also allows to define options that should always be added,
 either as options before any library details, or at the very end. For example: