argp: modified behaviour for empty group header

[Alex Regueiro <alexreg at gmail dot com>]

The following patch for argp-help.c causes a blank line to be left between groups of options in `âhelp` output. This now occurs when an argp_option with the `doc` field a null-string is specified as a group header; previously no blank line was left between groups, even if such an argp_option element was specified (c.f. http://www.gnu.org/software/libc/manual/html_node/Argp-Option-Vectors.html#Argp-Option-Vectors). This would appear to be sensible behaviour, and certainly doesnât detract from any usage case, as I see it. Incidentally, the behaviour for group headers where the `doc` field is non-empty is already sensible; it leaves a blank line in `âhelp` output, followed by the header text itself.

Attachment: glibc-argp-empty_header.patch
Description: Binary data