[Buildroot] [PATCH v2] package/openscap: add patch to enforce project as C project

["Alexis Lothoré via buildroot" <buildroot@buildroot.org>]

When the toolchain involved in openscap build does not support C++, the
configure step fails with the following error:

  -- Detecting CXX compiler ABI info
  -- Detecting CXX compiler ABI info - failed
  -- Check for working CXX compiler: /bin/false
  -- Check for working CXX compiler: /bin/false - broken
  CMake Error at /usr/share/cmake/Modules/CMakeTestCXXCompiler.cmake:73 (message):
    The C++ compiler

      "/bin/false"

    is not able to compile a simple test program.

    It fails with the following output:

      Change Dir: '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'

      Run Build Command(s): /usr/bin/cmake -E env VERBOSE=1 /usr/bin/make -f Makefile cmTC_1834b/fast
      make[1]: Entering directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
      /usr/bin/make  -f CMakeFiles/cmTC_1834b.dir/build.make CMakeFiles/cmTC_1834b.dir/build
      make[2]: Entering directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
      Building CXX object CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o /bin/false    -o CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o -c /home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI/testCXXCompiler.cxx
      make[2]: *** [CMakeFiles/cmTC_1834b.dir/build.make:81: CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o] Error 1
      make[2]: Leaving directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
      make[1]: *** [Makefile:134: cmTC_1834b/fast] Error 2
      make[1]: Leaving directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'

    CMake will not be able to correctly generate this project.
  Call Stack (most recent call first):
    CMakeLists.txt:11 (project)

  -- Configuring incomplete, errors occurred!
  make: *** [package/pkg-generic.mk:263: /home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/.stamp_configured] Error 1
  make: Leaving directory '/home/autobuild/autobuild/instance-6/buildroot'

The openscap project does not contain any C++ file, and so does not need
a C++ capable compiler. Bring the to-be-integrated-upstream patch
enforcing C language in CMakeLists.txt to prevent this build failure.

Fixes: https://autobuild.buildroot.org/results/1fe550ffa79f0a083a450ae03fe067a8ab7336be
Fixes: https://autobuild.buildroot.org/results/e9d52b52658544916022050c78dcb137ca6c97e0
Fixes: https://autobuild.buildroot.org/results/4a9c21763aaddb217ee5f8bb8947faad9767baa3
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
---
Changes in v2:
- fix upstream CMakeLists.txt rather than enabling C++ support in toolchain
- bring in the to-be-integrated-upstream corresponding patch
- Link to v1: https://lore.kernel.org/r/20260216-openscap_cpp-v1-1-3372149da5b0@bootlin.com
---
 .../openscap/0001-set-project-as-c-project.patch   | 78 ++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/package/openscap/0001-set-project-as-c-project.patch b/package/openscap/0001-set-project-as-c-project.patch
new file mode 100644
index 000000000000..c794fbaf44dc
--- /dev/null
+++ b/package/openscap/0001-set-project-as-c-project.patch
@@ -0,0 +1,78 @@
+From a742647efd215b682e4cd26b15ac3e580c10ef9f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Alexis=20Lothor=C3=A9?= <alexis.lothore@bootlin.com>
+Date: Mon, 16 Feb 2026 13:50:48 +0100
+Subject: [PATCH] Set project as C project in CMakeLists.txt
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+The openscap tool has been recently integrated in the buildroot build
+system ([1]), which makes the openscap tool buildable for a wide variety
+or architectures/OSes, with a wide variety of _compilers_. And so when
+such compilers are not supporting C++ projects (as it is the case with a
+default buildroot toolchain), the build breaks on the following error
+(see [2] for an example):
+
+  -- Detecting CXX compiler ABI info
+  -- Detecting CXX compiler ABI info - failed
+  -- Check for working CXX compiler: /bin/false
+  -- Check for working CXX compiler: /bin/false - broken
+  CMake Error at /usr/share/cmake/Modules/CMakeTestCXXCompiler.cmake:73 (message):
+    The C++ compiler
+
+      "/bin/false"
+
+    is not able to compile a simple test program.
+
+    It fails with the following output:
+
+      Change Dir: '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
+
+      Run Build Command(s): /usr/bin/cmake -E env VERBOSE=1 /usr/bin/make -f Makefile cmTC_1834b/fast
+      make[1]: Entering directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
+      /usr/bin/make  -f CMakeFiles/cmTC_1834b.dir/build.make CMakeFiles/cmTC_1834b.dir/build
+      make[2]: Entering directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
+      Building CXX object CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o
+      /bin/false    -o CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o -c /home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI/testCXXCompiler.cxx
+      make[2]: *** [CMakeFiles/cmTC_1834b.dir/build.make:81: CMakeFiles/cmTC_1834b.dir/testCXXCompiler.cxx.o] Error 1
+      make[2]: Leaving directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
+      make[1]: *** [Makefile:134: cmTC_1834b/fast] Error 2
+      make[1]: Leaving directory '/home/autobuild/autobuild/instance-6/output-1/build/openscap-1.3.12/buildroot-build/CMakeFiles/CMakeScratch/TryCompile-tUydqI'
+
+    CMake will not be able to correctly generate this project.
+  Call Stack (most recent call first):
+    CMakeLists.txt:11 (project)
+
+openscap does not have any C++ code to build, so restricting builds to
+toolchains supporting C++ is overconstraining, the configuration step
+should rather not try to check C++ support.
+
+Enforce the project as a C project in CMakeLists.txt to make sure not to
+test C++ features on the used toolchain.
+
+[1] https://buildroot.org/
+[2] https://autobuild.buildroot.org/results/1fe550ffa79f0a083a450ae03fe067a8ab7336be/build-end.log
+
+Upstream: https://github.com/OpenSCAP/openscap/pull/2312
+[patch slightly adapted to be applicable on v1.3.12]
+Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
+---
+ CMakeLists.txt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index cb13debb47cf..05b054327951 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -8,7 +8,7 @@ if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+ 		"MinSizeRel" "RelWithDebInfo")
+ endif()
+ 
+-project("openscap")
++project("openscap" C)
+ set(OPENSCAP_VERSION_MAJOR "1")
+ set(OPENSCAP_VERSION_MINOR "3")
+ set(OPENSCAP_VERSION_PATCH "12")
+-- 
+2.53.0
+

---
base-commit: 78d38d9ddda81d7c6bff9b520656fe4f46f0f692
change-id: 20260216-openscap_cpp-5e4035d7dbf8

Best regards,
-- 
Alexis Lothoré <alexis.lothore@bootlin.com>

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