Bug 1225919

GCC 14 newly by default treats as errors a number of situations which
before were only warnings.  For more information see
https://gcc.gnu.org/gcc-14/porting_to.html and meta bug #1220571.

Because of this, package rrdtool fails to compile.  This can be seen online
at:
https://build.opensuse.org/package/live_build_log/openSUSE:Factory:Staging:Gcc7/rrdtool/standard/x86_64

It can be reproduced locally with command: osc build --clean
--alternative-project home:rguenther:nextgcc

We probably need patches listed at:
https://gitlab.com/fweimer-rh/fedora-modernc/-/blob/main/pkg/r/rrdtool.md?ref_type=heads


The (first) error (that halts the build) is:

[   41s] rrd_tune.c: In function 'rrd_tune_r':
[   41s] rrd_tune.c:239:35: error: passing argument 3 of 'optparse_init' from incompatible pointer type [-Wincompatible-pointer-types]
[   41s]   239 |     optparse_init(&options, argc, argv); /* re-initialize optparse */
[   41s]       |                                   ^~~~
[   41s]       |                                   |
[   41s]       |                                   const char **
[   41s] In file included from rrd_tool.h:49,
[   41s]                  from rrd_tune.c:46:
[   41s] optparse.h:68:63: note: expected 'char **' but argument is of type 'const char **'
[   41s]    68 | void optparse_init(struct optparse *options, int argc, char **argv);
[   41s]       |                                                        ~~~~~~~^~~~