Subject: x2vnc: ftbfs with GCC-15

From: Matthias Klose <[email-masked]>
Date: Mon, 17 Feb 2025 18:00:57 +0000

Package: src:x2vnc
Version: 1.7.2+git20100909.01ced3d-1
Severity: important
Tags: sid forky
User: [email-masked]
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/x2vnc_1.7.2+git20100909.01ced3d-1_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

[...]
  127 |     sprintf(portstr, "%i", tunnel(gateway, remote, port));
      |                                            ^~~~~~
sockets.c:34:37: note: expected ‘char *’ but argument is of type ‘const char *’
   34 | int tunnel(char *gatewayhost, char *remotehost, int remoteport);
      |                               ~~~~~~^~~~~~~~~~
rfbproto.c:83:1: error: conflicting types for ‘InitialiseRFBConnection’; have ‘int(int)’
   83 | InitialiseRFBConnection(int sock)
      | ^~~~~~~~~~~~~~~~~~~~~~~
In file included from rfbproto.c:30:
./x2vnc.h:105:13: note: previous declaration of ‘InitialiseRFBConnection’ with type ‘int(void)’
  105 | extern Bool InitialiseRFBConnection();
      |             ^~~~~~~~~~~~~~~~~~~~~~~
x.c: In function ‘ungrabit’:
x.c:796:7: warning: ‘XKeycodeToKeysym’ is deprecated [-Wdeprecated-declarations]
  796 |       if (!SendKeyEvent(XKeycodeToKeysym(dpy, i, 0), False))
      |       ^~
In file included from ./x2vnc.h:28,
                 from x.c:28:
/usr/include/X11/Xlib.h:1683:15: note: declared here
 1683 | extern KeySym XKeycodeToKeysym(
      |               ^~~~~~~~~~~~~~~~
x2vnc.c: In function ‘main’:
x2vnc.c:62:38: warning: format ‘%d’ expects argument of type ‘int’, but argument 5 has type ‘time_t’ {aka ‘long int’} [-Wformat=]
   62 |       sprintf(tmpfile, "%s/x2vnc-%d-%d",
      |                                     ~^
      |                                      |
      |                                      int
      |                                     %ld
......
   65 |               time(0));
      |               ~~~~~~~                 
      |               |
      |               time_t {aka long int}
x2vnc.c:100:8: error: too many arguments to function ‘InitialiseRFBConnection’; expected 0, have 1
  100 |   if (!InitialiseRFBConnection(rfbsock)) exit(1);
      |        ^~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~
In file included from x2vnc.c:34:
./x2vnc.h:105:13: note: declared here
  105 | extern Bool InitialiseRFBConnection();
      |             ^~~~~~~~~~~~~~~~~~~~~~~
x.c: In function ‘HandleTopLevelEvent’:
x.c:1242:9: warning: ‘XKeycodeToKeysym’ is deprecated [-Wdeprecated-declarations]
 1242 |         ks = XKeycodeToKeysym(dpy, ev->xkey.keycode, 0);
      |         ^~
/usr/include/X11/Xlib.h:1683:15: note: declared here
 1683 | extern KeySym XKeycodeToKeysym(
      |               ^~~~~~~~~~~~~~~~
x.c:1260:32: warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument 3 has type ‘KeySym’ {aka ‘long unsigned int’} [-Wformat=]
 1260 |         fprintf(stderr,"  --> %x (%c) name=%s (%s)\n",ks,ks,keyname,
      |                               ~^                      ~~
      |                                |                      |
      |                                unsigned int           KeySym {aka long unsigned int}
      |                               %lx
x.c:1260:36: warning: format ‘%c’ expects argument of type ‘int’, but argument 4 has type ‘KeySym’ {aka ‘long unsigned int’} [-Wformat=]
 1260 |         fprintf(stderr,"  --> %x (%c) name=%s (%s)\n",ks,ks,keyname,
      |                                   ~^                     ~~
      |                                    |                     |
      |                                    int                   KeySym {aka long unsigned int}
      |                                   %ld
rfbproto.c: In function ‘InitialiseRFBConnection’:
rfbproto.c:223:28: warning: ignoring return value of ‘ftruncate’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  223 |           if(temp_file_fd) ftruncate(temp_file_fd, 0);
      |                            ^~~~~~~~~~~~~~~~~~~~~~~~~~
make[1]: *** [<builtin>: x2vnc.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make[1]: *** [<builtin>: rfbproto.o] Error 1
make[1]: Leaving directory '/build/reproducible-path/x2vnc-1.7.2+git20100909.01ced3d'
dh_auto_build: error: make -j8 returned exit code 2
make: *** [debian/rules:10: binary] Error 25
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2