* builtins.c (fold_builtin_1): Treat ccos and ccosh as 'even'
	functions.

	* fold-const.c (negate_mathfn_p): Treat casin, casinh, catan,
	catanh, cproj, csin, csinh, ctan and ctanh as 'odd' functions.
	
testsuite:
	* gcc.dg/builtins-20.c: Add more cases.
	* gcc.dg/torture/builtin-symmetric-1.c: Likewise.

From-SVN: r121200