Bug#1096703: ghc: ftbfs with GCC-15

[Matthias Klose]

Package: src:ghc
Version: 9.6.6-3
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/ghc_9.6.6-3_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

[...]

utils/hp2ps/Utilities.c:80:17: error:
     error: too many arguments to function ‘malloc’; expected 0, have 1
       80 |     r = (void*) malloc(n);
          |                 ^~~~~~ ~
   |
80 |     r = (void*) malloc(n);
   |                 ^

utils/hp2ps/Utilities.c:6:14: error:
     note: declared here
        6 | extern void* malloc();
          |              ^~~~~~
  |
6 | extern void* malloc();
  |              ^
utils/hp2ps/Utilities.c: In function ‘xrealloc’:

utils/hp2ps/Utilities.c:92:18: error:
     warning: conflicting types for built-in function ‘realloc’; expected ‘void *(void *, long unsigned int)’ [-Wbuiltin-declaration-mismatch]
       92 |     extern void *realloc();
          |                  ^~~~~~~
   |
92 |     extern void *realloc();
   |                  ^

utils/hp2ps/Utilities.c:92:18: error:
     note: ‘realloc’ is declared in header ‘<stdlib.h>’
   |
92 |     extern void *realloc();
   |                  ^

utils/hp2ps/Utilities.c:94:9: error:
     error: too many arguments to function ‘realloc’; expected 0, have 2
       94 |     r = realloc(p, n);
          |         ^~~~~~~ ~
   |
94 |     r = realloc(p, n);
   |         ^

utils/hp2ps/Utilities.c:92:18: error:
     note: declared here
       92 |     extern void *realloc();
          |                  ^~~~~~~
   |
92 |     extern void *realloc();
   |                  ^
At top level:
cc1: note: unrecognized command-line option ‘-Wno-nonportable-include-path’ may have been intended to silence earlier diagnostics
`x86_64-linux-gnu-gcc' failed in phase `C Compiler'. (Exit code: 1)
Error when running Shake build system:
  at want, called at src/Main.hs:124:44 in main:Main
* Depends on: binary-dist-dir
  at need, called at src/Rules/BinaryDist.hs:130:9 in main:Rules.BinaryDist
* Depends on: _build/stage1/bin/hp2ps
  at need, called at src/Rules/Program.hs:129:5 in main:Rules.Program
* Depends on: _build/stage1/utils/hp2ps/build/c/Utilities.dyn_o
  at cmd', called at src/Builder.hs:387:23 in main:Builder
  at cmdArgs, called at src/Builder.hs:540:8 in main:Builder
  at cmdArgs, called at src/Builder.hs:564:18 in main:Builder
  at cmdArgs, called at src/Builder.hs:564:18 in main:Builder
  at error, called at src/Builder.hs:609:13 in main:Builder
* Raised the exception:
Command failed

Build failed.
make[1]: *** [debian/rules:176: override_dh_auto_build-arch] Error 1
make[1]: Leaving directory '/build/reproducible-path/ghc-9.6.6'
make: *** [debian/rules:132: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2