Bug#1096539: dot-forward: ftbfs with GCC-15

[Matthias Klose <doko@debian.org>]

Package: src:dot-forward
Version: 1:0.71-8
Severity: important
Tags: sid forky
User: debian-gcc@lists.debian.org
Usertags: ftbfs-gcc-15

[This bug is NOT targeted to the upcoming trixie release]

Please keep this issue open in the bug tracker for the package it
was filed for.  If a fix in another package is required, please
file a bug for the other package (or clone), and add a block in this
package. Please keep the issue open until the package can be built in
a follow-up test rebuild.

The package fails to build in a test rebuild on at least amd64 with
gcc-15/g++-15, but succeeds to build with gcc-14/g++-14. The
severity of this report will be raised before the forky release.

The full build log can be found at:
http://qa-logs.debian.net/2025/02/16/amd64exp/dot-forward_0.71-8_unstable_gccexp.log.gz
The last lines of the build log are at the end of this report.

To build with GCC 15, either set CC=gcc-15 CXX=g++-15 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t=experimental install g++ 

GCC 15 now defaults to the C23/C++23 standards, exposing many FTBFS.
Other Common build failures are new warnings resulting in build failures
with -Werror turned on, or new/dropped symbols in Debian symbols files.
For other C/C++ related build failures see the porting guide at
http://gcc.gnu.org/gcc-15/porting_to.html

[...]
      |     ^~~~~~~~~~~~~~
substdo.c:92:1: error: number of arguments doesn’t match prototype
   92 | {
      | ^
substdio.h:23:12: error: prototype declaration
   23 | extern int substdio_bputs();
      |            ^~~~~~~~~~~~~~
substdo.c:93:30: error: too many arguments to function ‘str_len’; expected 0, have 1
   93 |   return substdio_bput(s,buf,str_len(buf));
      |                              ^~~~~~~ ~~~
In file included from substdo.c:2:
str.h:7:21: note: declared here
    7 | extern unsigned int str_len();
      |                     ^~~~~~~
substdo.c:93:10: error: too many arguments to function ‘substdio_bput’; expected 0, have 3
   93 |   return substdio_bput(s,buf,str_len(buf));
      |          ^~~~~~~~~~~~~ ~
substdo.c:38:5: note: declared here
   38 | int substdio_bput(s,buf,len)
      |     ^~~~~~~~~~~~~
substdo.c: In function ‘substdio_puts’:
substdo.c:96:5: warning: old-style function definition [-Wold-style-definition]
   96 | int substdio_puts(s,buf)
      |     ^~~~~~~~~~~~~
substdo.c:99:1: error: number of arguments doesn’t match prototype
   99 | {
      | ^
substdio.h:22:12: error: prototype declaration
   22 | extern int substdio_puts();
      |            ^~~~~~~~~~~~~
substdo.c:100:29: error: too many arguments to function ‘str_len’; expected 0, have 1
  100 |   return substdio_put(s,buf,str_len(buf));
      |                             ^~~~~~~ ~~~
str.h:7:21: note: declared here
    7 | extern unsigned int str_len();
      |                     ^~~~~~~
substdo.c:100:10: error: too many arguments to function ‘substdio_put’; expected 0, have 3
  100 |   return substdio_put(s,buf,str_len(buf));
      |          ^~~~~~~~~~~~ ~
substdo.c:55:5: note: declared here
   55 | int substdio_put(s,buf,len)
      |     ^~~~~~~~~~~~
substdo.c: In function ‘substdio_putsflush’:
substdo.c:103:5: warning: old-style function definition [-Wold-style-definition]
  103 | int substdio_putsflush(s,buf)
      |     ^~~~~~~~~~~~~~~~~~
substdo.c:106:1: error: number of arguments doesn’t match prototype
  106 | {
      | ^
substdio.h:24:12: error: prototype declaration
   24 | extern int substdio_putsflush();
      |            ^~~~~~~~~~~~~~~~~~
substdo.c:107:34: error: too many arguments to function ‘str_len’; expected 0, have 1
  107 |   return substdio_putflush(s,buf,str_len(buf));
      |                                  ^~~~~~~ ~~~
str.h:7:21: note: declared here
    7 | extern unsigned int str_len();
      |                     ^~~~~~~
substdo.c:107:10: error: too many arguments to function ‘substdio_putflush’; expected 0, have 3
  107 |   return substdio_putflush(s,buf,str_len(buf));
      |          ^~~~~~~~~~~~~~~~~ ~
substdo.c:80:5: note: declared here
   80 | int substdio_putflush(s,buf,len)
      |     ^~~~~~~~~~~~~~~~~
make[1]: *** [Makefile:379: substdio_copy.o] Error 1
make[1]: *** [Makefile:383: substdo.o] Error 1
make[1]: Leaving directory '/build/reproducible-path/dot-forward-0.71'
dh_auto_build: error: make -j8 "INSTALL=install --strip-program=true" returned exit code 2
make: *** [debian/rules:8: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2