[ARROW-11023] [C++][CMake] gRPC doesn't respect CMAKE_CXX_COMPILER

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/26942
• Assignee: Yibo Cai
• Reporter: Yibo Cai
• Created: 24/Dec/20 04:18
• Updated: 11/Jan/23 08:17
• Resolved: 24/Dec/20 07:50

Description

I have both gcc and clang installed. gcc is the default compiler, /usr/bin/c++ points to g++.
When build flight with clang, it failed with below message.

$ cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DARROW_FLIGHT=ON -DARROW_WITH_ZLIB=ON -DCMAKE_CXX_COMPILER=/usr/bin/clang++-9 -DCMAKE_C_COMPILER=/usr/bin/clang-9 ..

$ ninja

    /usr/bin/c++    -Qunused-arguments -fcolor-diagnostics -O3 -DNDEBUG -O3 -DNDEBUG -fPIC -o CMakeFiles/cmTC_0ad35.dir/testCXXCompiler.cxx.o -c testCXXCompiler.cxx
    c++: error: unrecognized command line option ‘-Qunused-arguments’; did you mean ‘-Wunused-parameter’?
    c++: error: unrecognized command line option ‘-fcolor-diagnostics’

The reason is grpc/absl/cares building steps don't respect CMAKE_CXX_COMPILER and CMAKE_C_COMPILER.
They're always built with system default compiler.

Issue Links

• links to: GitHub Pull Request #9002