test-signbit: avoid tripping Irix cc bug on -0.0L * tests/test-signbit.c (minus_zerol): Delete, and replace with '-zerol'. This may break on HP-UX/hppa, but at least makes the entire testsuite consistent and avoids an Irix 6.2 bug. Signed-off-by: Eric Blake <ebb9@byu.net>