This patch is to add _Complex type in vararg testing.

Run varargs.exp on i686-pc-linux-gnu, get new two KFAIL.  Note that PR
12776 is opened to track this problem.

KFAIL: gdb.base/varargs.exp: print find_max_double_real(4, dc1, dc2,
dc3, dc4) (PRMS: gdb/12776)
KFAIL: gdb.base/varargs.exp: print find_max_double_real(4, dc1, dc2,
dc3, dc4) (PRMS: gdb/12776)

                === gdb Summary ===

# of expected passes            9
# of known failures             2

-- 
Yao (齐尧)