Assign the set of default rewrites used by rewriting and simplification.
DESCRIPTION
The HOL Light rewriter (REWRITE_TAC etc.) and simplifier (SIMP_TAC etc.)
have default sets of (conditional) equations and other conversions that are
applied by default, except in the PURE_ variants. A call to
extend_basic_rewrites thl sets this to be the list of theorems thl (after
processing into rewrite rules by mk_rewrites).
FAILURE CONDITIONS
Never fails.
COMMENTS
Users will most likely want to extend the existing set by
extend_basic_rewrites rather than completely change it like this.