Before = dpv: <__func__>: posix_spawnp(3): No such file or directory
After = dpv: <path/cmd>: No such file or directory
Most notably, show the 2nd argument being passed to posix_spawnp(3)
so we know what path/cmd failed.
Also, we don't need to have "posix_spawnp(3)" in the error message
nor the function because that can [a] change and [b] traversed using
a debugger if necessary.
GCC 5.2.0 generates the following [fatal] warning:
dialog_util.c:270:23: error:
zero-length gnu_printf format string [-Werror=format-zero-length]
sprintf(dargv[n++], "");
Fix malloc argument while here, removing sprintf.
Reported by: Ruslan Bukin <ruslan.bukin at cl cam ac uk>
dialog(3)'s dlg_reallocate_gauge(), used both by dialog(3)'s dialog_gauge()
and dialog(1)'s `--gauge', will segmentation fault in strlen(3) if no title
is set for the widget. Reproducible with `dialog --gauge hi 6 20' (adding
`--title ""' is enough to prevent segmentation fault).
MFC after: 3 days
X-MFC-to: stable/10
