x86 LEA instruction for multiplication by constants.
* bug fix: in some situations compiler did not report usage of
generic arithmetic in (SPEED 3) policy.
+ * fixed some bugs revealed by Paul Dietz' test suite:
+ ** the RETURN clause in LOOP is now equivalent to DO (RETURN ...).
+ ** ROUND and FROUND now give the right answer when given very
+ small float arguments.
planned incompatible changes in 0.8.x:
* (not done yet, but planned:) When the profiling interface settles