Bug#1096601: exim4: ftbfs with GCC-15

[Matthias Klose]

Package: src:exim4
Version: 4.98-3
Severity: important
Tags: sid forky
User: debian-gcc at 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/exim4_4.98-3_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

[...]
                 from ../exim_monitor/em_StripChart.c:41:
/usr/include/X11/Intrinsic.h:990:5: note: expected 'XtTimerCallbackProc' {aka 'void (*)(void *, long unsigned int *)'} but argument is of type 'void (*)(void)'
  990 |     XtTimerCallbackProc /* proc */,
      |     ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c:135:13: note: 'draw_it' declared here
  135 | static void draw_it();
      |             ^~~~~~~
/usr/include/X11/Intrinsic.h:309:16: note: 'XtTimerCallbackProc' declared here
  309 | typedef void (*XtTimerCallbackProc)(
      |                ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c: In function 'Destroy':
../exim_monitor/em_StripChart.c:201:13: warning: old-style function definition [-Wold-style-definition]
  201 | static void Destroy (gw)
      |             ^~~~~~~
../exim_monitor/em_StripChart.c: In function 'Redisplay':
../exim_monitor/em_StripChart.c:220:13: warning: old-style function definition [-Wold-style-definition]
  220 | static void Redisplay(w, event, region)
      |             ^~~~~~~~~
../exim_monitor/em_StripChart.c: In function 'draw_it':
../exim_monitor/em_StripChart.c:235:1: warning: old-style function definition [-Wold-style-definition]
  235 | draw_it(client_data, id)
      | ^~~~~~~
../exim_monitor/em_StripChart.c:245:59: error: passing argument 3 of 'XtAppAddTimeOut' from incompatible pointer type [-Wincompatible-pointer-types]
  245 |                        w->strip_chart.update * MS_PER_SEC,draw_it,client_data);
      |                                                           ^~~~~~~
      |                                                           |
      |                                                           void (*)(void)
/usr/include/X11/Intrinsic.h:990:5: note: expected 'XtTimerCallbackProc' {aka 'void (*)(void *, long unsigned int *)'} but argument is of type 'void (*)(void)'
  990 |     XtTimerCallbackProc /* proc */,
      |     ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c:235:1: note: 'draw_it' declared here
  235 | draw_it(client_data, id)
      | ^~~~~~~
/usr/include/X11/Intrinsic.h:309:16: note: 'XtTimerCallbackProc' declared here
  309 | typedef void (*XtTimerCallbackProc)(
      |                ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c: In function 'repaint_window':
../exim_monitor/em_StripChart.c:306:1: warning: old-style function definition [-Wold-style-definition]
  306 | repaint_window(w, left, width)
      | ^~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c: In function 'SetValues':
../exim_monitor/em_StripChart.c:434:16: warning: old-style function definition [-Wold-style-definition]
  434 | static Boolean SetValues (current, request, new)
      |                ^~~~~~~~~
../exim_monitor/em_StripChart.c:449:33: error: passing argument 3 of 'XtAppAddTimeOut' from incompatible pointer type [-Wincompatible-pointer-types]
  449 |                                 draw_it, (XtPointer)w);
      |                                 ^~~~~~~
      |                                 |
      |                                 void (*)(void)
/usr/include/X11/Intrinsic.h:990:5: note: expected 'XtTimerCallbackProc' {aka 'void (*)(void *, long unsigned int *)'} but argument is of type 'void (*)(void)'
  990 |     XtTimerCallbackProc /* proc */,
      |     ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c:235:1: note: 'draw_it' declared here
  235 | draw_it(client_data, id)
      | ^~~~~~~
/usr/include/X11/Intrinsic.h:309:16: note: 'XtTimerCallbackProc' declared here
  309 | typedef void (*XtTimerCallbackProc)(
      |                ^~~~~~~~~~~~~~~~~~~
../exim_monitor/em_StripChart.c: In function 'SetPoints':
../exim_monitor/em_StripChart.c:481:1: warning: old-style function definition [-Wold-style-definition]
  481 | SetPoints(w)
      | ^~~~~~~~~
make[3]: *** [Makefile:1073: em_StripChart.o] Error 1
make[3]: Leaving directory '/build/reproducible-path/exim4-4.98/b-exim4-daemon-light/build-Linux-x86_64'
make[2]: *** [Makefile:37: all] Error 2
make[2]: Leaving directory '/build/reproducible-path/exim4-4.98/b-exim4-daemon-light'
make[1]: *** [debian/rules:121: override_dh_auto_build] Error 2
make[1]: Leaving directory '/build/reproducible-path/exim4-4.98'
make: *** [debian/rules:329: build] Error 2
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2