Bug#973395: clang-10: Unable to package LLVM/Clang on Buster (for backports) - libffi error

[Maxime Lombard]

Package: clang-10
Version: 1:10.0.1-6
Severity: normal

Dear Maintainer,

I'm an user of Debian Buster and i tried to backport LLVM-10 from Testing to have the latest version of Mesa.
There are no issues when i package LLVM for AMD64 architecture, the problem appears only when i package for i386 arch.

To package LLVM for stable-backports, i use pbuilder and i use this command : 
"ARCH=i386 DIST=stable pdebuild" (i used the PbuilderTricks wiki)

I tried to do the same thing with LLVM-11 and same problem. Works with AMD64 and crash with i386.

The error message in .build file is : 

[...]
CMake Error at cmake/config-ix.cmake:321 (message):
  libffi includes are not found.
Call Stack (most recent call first):
  CMakeLists.txt:655 (include)


-- Configuring incomplete, errors occurred!
See also "/build/llvm-toolchain-11-11.0.0/build-llvm/tools/clang/stage2-bins/CMakeFiles/CMakeOutput.log".
See also "/build/llvm-toolchain-11-11.0.0/build-llvm/tools/clang/stage2-bins/CMakeFiles/CMakeError.log".
make[5]: *** [tools/clang/CMakeFiles/stage2.dir/build.make:109: tools/clang/stage2-stamps/stage2-configure] Error 1
make[5]: Leaving directory '/build/llvm-toolchain-11-11.0.0/build-llvm'
make[4]: *** [CMakeFiles/Makefile2:50134: tools/clang/CMakeFiles/stage2.dir/all] Error 2
make[4]: Leaving directory '/build/llvm-toolchain-11-11.0.0/build-llvm'
make[3]: *** [CMakeFiles/Makefile2:50141: tools/clang/CMakeFiles/stage2.dir/rule] Error 2
make[3]: Leaving directory '/build/llvm-toolchain-11-11.0.0/build-llvm'
make[2]: *** [Makefile:14983: stage2] Error 2
make[2]: Leaving directory '/build/llvm-toolchain-11-11.0.0/build-llvm'
make[1]: *** [debian/rules:408: debian-full-build] Error 2
make[1]: Leaving directory '/build/llvm-toolchain-11-11.0.0'
make: *** [debian/rules:291: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2
[...]

Obviously, libffi-dev package is installed at the beginning.
I tried to backports libffi too without success.

Thanks for your help,


-- System Information:
Debian Release: 10.6
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.8.0-0.bpo.2-amd64 (SMP w/8 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled