* c-decl.c (finish_enum): Simplify code to determine minimum and
maximum values of the enum, and calculate the type. Remove check
for FUNCTION_DECLs in the values list, which cannot happen. Replace
the DECL_INITIAL of each enumeration constant with a copy converted
to the enumeration type. When updating variant types, don't bother
updating the type itself.
* c-typeck.c (build_binary_op): Simplify conditional expressions
when weeding out spurious signed-unsigned warnings. Add new
spurious warning category: if the unsigned quantity is an enum
and its maximum value fits in signed_type(result_type). Update
commentary.
(build_conditional_expr): Warn here if one alternative is signed
and the other is unsigned.