core: Add gpgrt_fnameconcat and gpgrt_absfnameconcat.
* src/gpg-error.h.in (gpgrt_fnameconcat): New. (gpgrt_absfnameconcat): New. * src/visibility.c (gpgrt_fnameconcat, gpgrt_absfnameconcat): New. * src/stringutils.c: New file. (_gpgrt_vfnameconcat): New. (_gpgrt_fnameconcat, _gpgrt_absfnameconcat): New. * src/gpg-error.def.in: Add new functions. * src/gpg-error.vers: Ditto. * src/sysutils.c: Include pwd.h. (_gpgrt_getpwdir): New. * configure.ac: Test for pwd.h, getpwnam, getpwuid, and their _r variants. * src/Makefile.am (libgpg_error_la_SOURCES): Add new file. * tests/t-stringutils.c: New. * tests/t-common.h (xmalloc, xstrdup, xfree): New. (die): Kludge to avoid compiler warnings.
The new functions are based on the code of make_filename from GnuPG.
They have been written by me ages ago with only minor modifications by
David Shaw. I re-license them from LGPL-3.0+ OR GPL-2.0+ to
LGPL-2.1-or-later.
- Signed-off-by: Werner Koch <wk@gnupg.org>