a bug in the TIOCGWINSZ ioctl on at least Solaris5.9 systems. Setting
either (or both) to zero would succeed, but subsequent `stty size'
would say `no size information for this device' due to the ioctl
failing with EINVAL.
tests='
1 rows_40_columns_80 40_80
-2 rows_0_columns_0 0_0
+2 rows_1_columns_1 1_1
3 rows_40_columns_80 40_80
-4 rows_0 0_80
-5 columns_0 0_0
-6 rows_40 40_0
-7 rows_0 0_0
-8 columns_80 0_80
+4 rows_1 1_80
+5 columns_1 1_1
+6 rows_40 40_1
+7 rows_1 1_1
+8 columns_80 1_80
9 rows_30 30_80
NA LAST NA
'