workflows: add sanity check for toolchains w/ CXX support

.github/workflows/pr-compile-check.yaml

@@ -102,3 +102,26 @@ jobs:
           echo "$ldd_result" | grep libsqlite3
           echo "$ldd_result" | grep libzstd
         working-directory: build
+
+  # Sanity check for compilation w/ CXX support
+  pr-compile-without-cxx:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 60
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Setup environment
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y bison cmake flex gcc libssl-dev libyaml-dev
+
+      - name: Checkout Fluent Bit code
+        uses: actions/checkout@v4
+
+      - name: Compile w/ CXX support
+        run: |
+          export CXX=/bin/false
+          export nparallel=$(( $(getconf _NPROCESSORS_ONLN) > 8 ? 8 : $(getconf _NPROCESSORS_ONLN) ))
+          cmake ../
+          make -j $nparallel
+        working-directory: build

lib/librdkafka-2.8.0/CMakeLists.txt

@@ -3,7 +3,16 @@ cmake_minimum_required(VERSION 3.5)
 include("packaging/cmake/parseversion.cmake")
 parseversion("src/rdkafka.h")
 
-project(RdKafka VERSION ${RDKAFKA_VERSION})
+project(RdKafka VERSION ${RDKAFKA_VERSION} LANGUAGES C)
+
+# Check for CXX support
+include(CheckLanguage)
+check_language(CXX)
+if(CMAKE_CXX_COMPILER)
+  enable_language(CXX)
+else()
+  message(STATUS "C++ compiler not found, skipping C++ support")
+endif()
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/packaging/cmake/Modules/")
 
@@ -181,7 +190,11 @@ endif()
 
 option(RDKAFKA_BUILD_STATIC "Build static rdkafka library" OFF)
 option(RDKAFKA_BUILD_EXAMPLES "Build examples" ON)
-option(RDKAFKA_BUILD_TESTS "Build tests" ON)
+
+if(CMAKE_CXX_COMPILER)
+    option(RDKAFKA_BUILD_TESTS "Build tests" ON)
+endif()
+
 if(WIN32)
     option(WITHOUT_WIN32_CONFIG "Avoid including win32_config.h on cmake builds" ON)
 endif(WIN32)
@@ -279,7 +292,10 @@ install(
 )
 
 add_subdirectory(src)
-add_subdirectory(src-cpp)
+
+if(CMAKE_CXX_COMPILER)
+  add_subdirectory(src-cpp)
+endif()
 
 if(RDKAFKA_BUILD_EXAMPLES)
   add_subdirectory(examples)

lib/librdkafka-2.8.0/examples/CMakeLists.txt

@@ -5,23 +5,31 @@ endif(WIN32)
 add_executable(producer producer.c ${win32_sources})
 target_link_libraries(producer PUBLIC rdkafka)
 
-add_executable(producer_cpp producer.cpp ${win32_sources})
-target_link_libraries(producer_cpp PUBLIC rdkafka++)
+if(CMAKE_CXX_COMPILER)
+    add_executable(producer_cpp producer.cpp ${win32_sources})
+    target_link_libraries(producer_cpp PUBLIC rdkafka++)
+endif()
 
 add_executable(consumer consumer.c ${win32_sources})
 target_link_libraries(consumer PUBLIC rdkafka)
 
 add_executable(rdkafka_performance rdkafka_performance.c ${win32_sources})
 target_link_libraries(rdkafka_performance PUBLIC rdkafka)
 
-add_executable(rdkafka_example_cpp rdkafka_example.cpp ${win32_sources})
-target_link_libraries(rdkafka_example_cpp PUBLIC rdkafka++)
+if(CMAKE_CXX_COMPILER)
+    add_executable(rdkafka_example_cpp rdkafka_example.cpp ${win32_sources})
+    target_link_libraries(rdkafka_example_cpp PUBLIC rdkafka++)
+endif()
 
-add_executable(rdkafka_complex_consumer_example_cpp rdkafka_complex_consumer_example.cpp ${win32_sources})
-target_link_libraries(rdkafka_complex_consumer_example_cpp PUBLIC rdkafka++)
+if(CMAKE_CXX_COMPILER)
+    add_executable(rdkafka_complex_consumer_example_cpp rdkafka_complex_consumer_example.cpp ${win32_sources})
+    target_link_libraries(rdkafka_complex_consumer_example_cpp PUBLIC rdkafka++)
+endif()
 
-add_executable(openssl_engine_example_cpp openssl_engine_example.cpp ${win32_sources})
-target_link_libraries(openssl_engine_example_cpp PUBLIC rdkafka++)
+if(CMAKE_CXX_COMPILER)
+    add_executable(openssl_engine_example_cpp openssl_engine_example.cpp ${win32_sources})
+    target_link_libraries(openssl_engine_example_cpp PUBLIC rdkafka++)
+endif()
 
 add_executable(misc misc.c ${win32_sources})
 target_link_libraries(misc PUBLIC rdkafka)
@@ -73,7 +81,8 @@ if(NOT WIN32)
     add_executable(rdkafka_complex_consumer_example rdkafka_complex_consumer_example.c)
     target_link_libraries(rdkafka_complex_consumer_example PUBLIC rdkafka)
 
-    add_executable(kafkatest_verifiable_client kafkatest_verifiable_client.cpp)
-    target_link_libraries(kafkatest_verifiable_client PUBLIC rdkafka++)
-
+    if(CMAKE_CXX_COMPILER)
+        add_executable(kafkatest_verifiable_client kafkatest_verifiable_client.cpp)
+        target_link_libraries(kafkatest_verifiable_client PUBLIC rdkafka++)
+    endif()
 endif(NOT WIN32)

lib/luajit-cmake/CMakeLists.txt

@@ -13,7 +13,7 @@ endif()
 
 get_directory_property(hasParent PARENT_DIRECTORY)
 if(LUAJIT_DIR)
-  project(luajit)
+  project(luajit LANGUAGES C)
   include(LuaJIT.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:luajit> PARENT_SCOPE)
@@ -24,7 +24,7 @@ if(LUAJIT_DIR)
     endif()
   endif()
 elseif(LUA_DIR)
-  project(lua)
+  project(lua LANGUAGES C)
   include(lua.cmake)
   if (hasParent)
     set(LUA_TARGET $<TARGET_FILE:lua> PARENT_SCOPE)

lib/miniz/CMakeLists.txt

@@ -7,7 +7,7 @@ if(DEFINED PROJECT_NAME)
 endif()
 
 if(CMAKE_MINOR_VERSION LESS 12)
-  project(miniz)
+  project(miniz C)
   # see issue https://gitlab.kitware.com/cmake/cmake/merge_requests/1799
 else()
   project(miniz C)

lib/zstd-1.5.7/build/cmake/CMakeLists.txt

@@ -37,7 +37,6 @@ project(zstd
   VERSION "${ZSTD_FULL_VERSION}"
   LANGUAGES C   # Main library is in C
             ASM # And ASM
-            CXX # Testing contributed code also utilizes CXX
   )
 
 message(STATUS "ZSTD VERSION: ${zstd_VERSION}")
@@ -54,12 +53,6 @@ endif()
 
 include(GNUInstallDirs)
 
-#-----------------------------------------------------------------------------
-# Add extra compilation flags
-#-----------------------------------------------------------------------------
-include(AddZstdCompilationFlags)
-ADD_ZSTD_COMPILATION_FLAGS()
-
 # Always hide XXHash symbols
 add_definitions(-DXXH_NAMESPACE=ZSTD_)
 
@@ -123,6 +116,19 @@ if (MSVC)
     option(ZSTD_USE_STATIC_RUNTIME "LINK TO STATIC RUN-TIME LIBRARIES" OFF)
 endif ()
 
+# Enable C++ support for testing.
+set(ZSTD_ENABLE_CXX ${ZSTD_BUILD_TESTS})
+
+if(ZSTD_ENABLE_CXX)
+    enable_language(CXX)
+endif()
+
+#-----------------------------------------------------------------------------
+# Add extra compilation flags
+#-----------------------------------------------------------------------------
+include(AddZstdCompilationFlags)
+ADD_ZSTD_COMPILATION_FLAGS(ON ZSTD_ENABLE_CXX ON) # C CXX LD
+
 #-----------------------------------------------------------------------------
 # External dependencies
 #-----------------------------------------------------------------------------

lib/zstd-1.5.7/build/cmake/CMakeModules/AddZstdCompilationFlags.cmake

@@ -49,7 +49,7 @@ function(EnableCompilerFlag _flag _C _CXX _LD)
     endif ()
 endfunction()
 
-macro(ADD_ZSTD_COMPILATION_FLAGS)
+macro(ADD_ZSTD_COMPILATION_FLAGS _C _CXX _LD)
     # We set ZSTD_HAS_NOEXECSTACK if we are certain we've set all the required
     # compiler flags to mark the stack as non-executable.
     set(ZSTD_HAS_NOEXECSTACK false)
@@ -63,26 +63,26 @@ macro(ADD_ZSTD_COMPILATION_FLAGS)
         # EnableCompilerFlag("-std=c99" true false)   # Set C compilation to c99 standard
         if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND MSVC)
             # clang-cl normally maps -Wall to -Weverything.
-            EnableCompilerFlag("/clang:-Wall" true true false)
+            EnableCompilerFlag("/clang:-Wall" _C _CXX false)
         else ()
-            EnableCompilerFlag("-Wall" true true false)
+            EnableCompilerFlag("-Wall" _C _CXX false)
         endif ()
-        EnableCompilerFlag("-Wextra" true true false)
-        EnableCompilerFlag("-Wundef" true true false)
-        EnableCompilerFlag("-Wshadow" true true false)
-        EnableCompilerFlag("-Wcast-align" true true false)
-        EnableCompilerFlag("-Wcast-qual" true true false)
-        EnableCompilerFlag("-Wstrict-prototypes" true false false)
+        EnableCompilerFlag("-Wextra" _C _CXX false)
+        EnableCompilerFlag("-Wundef" _C _CXX false)
+        EnableCompilerFlag("-Wshadow" _C _CXX false)
+        EnableCompilerFlag("-Wcast-align" _C _CXX false)
+        EnableCompilerFlag("-Wcast-qual" _C _CXX false)
+        EnableCompilerFlag("-Wstrict-prototypes" _C false false)
         # Enable asserts in Debug mode
         if (CMAKE_BUILD_TYPE MATCHES "Debug")
-            EnableCompilerFlag("-DDEBUGLEVEL=1" true true false)
+            EnableCompilerFlag("-DDEBUGLEVEL=1" _C _CXX false)
         endif ()
         # Add noexecstack flags
         # LDFLAGS
-        EnableCompilerFlag("-Wl,-z,noexecstack" false false true)
+        EnableCompilerFlag("-Wl,-z,noexecstack" false false _LD)
         # CFLAGS & CXXFLAGS
-        EnableCompilerFlag("-Qunused-arguments" true true false)
-        EnableCompilerFlag("-Wa,--noexecstack" true true false)
+        EnableCompilerFlag("-Qunused-arguments" _C _CXX false)
+        EnableCompilerFlag("-Wa,--noexecstack" _C _CXX false)
         # NOTE: Using 3 nested ifs because the variables are sometimes
         # empty if the condition is false, and sometimes equal to false.
         # This implicitly converts them to truthy values. There may be
@@ -99,15 +99,15 @@ macro(ADD_ZSTD_COMPILATION_FLAGS)
 
         set(ACTIVATE_MULTITHREADED_COMPILATION "ON" CACHE BOOL "activate multi-threaded compilation (/MP flag)")
         if (CMAKE_GENERATOR MATCHES "Visual Studio" AND ACTIVATE_MULTITHREADED_COMPILATION)
-            EnableCompilerFlag("/MP" true true false)
+            EnableCompilerFlag("/MP" _C _CXX false)
         endif ()
 
         # UNICODE SUPPORT
-        EnableCompilerFlag("/D_UNICODE" true true false)
-        EnableCompilerFlag("/DUNICODE" true true false)
+        EnableCompilerFlag("/D_UNICODE" _C _CXX false)
+        EnableCompilerFlag("/DUNICODE" _C _CXX false)
         # Enable asserts in Debug mode
         if (CMAKE_BUILD_TYPE MATCHES "Debug")
-            EnableCompilerFlag("/DDEBUGLEVEL=1" true true false)
+            EnableCompilerFlag("/DDEBUGLEVEL=1" _C _CXX false)
         endif ()
     endif ()