[C++][Flight] Misleading CMake errors

[asfimport]

When building Arrow, one can get errors such as the following

-- Build output: Change Dir: /home/antoine/arrow/dev/cpp/build-test/src/arrow/flight/try_compile/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_cfc86 && [1/2] Building CXX object CMakeFiles/cmTC_cfc86.dir/check_tls_opts_132.cc.o
FAILED: CMakeFiles/cmTC_cfc86.dir/check_tls_opts_132.cc.o 
/usr/bin/g++-9  -I/home/antoine/arrow/dev/cpp/thirdparty/flatbuffers/include -I/home/antoine/arrow/dev/cpp/build-test/jemalloc_ep-prefix/src -I/home/antoine/arrow/dev/cpp/build-test/mimalloc_ep/src/mimalloc_ep/lib/mimalloc-1.6/include -I/home/antoine/arrow/dev/cpp/thirdparty/hadoop/include -I/home/antoine/arrow/dev/cpp/build-test/src -I/home/antoine/arrow/dev/cpp/src -I/home/antoine/arrow/dev/cpp/src/generated -isystem /home/antoine/miniconda3/envs/pyarrow/include -Wno-noexcept-type  -fdiagnostics-color=always -fuse-ld=gold -ggdb -O0  -Wall -Wno-conversion -Wno-deprecated-declarations -Wno-sign-conversion -Wno-unused-variable  -fno-semantic-interposition -march=haswell -mavx2  -D_GLIBCXX_USE_CXX11_ABI=1 -D_GLIBCXX_USE_CXX11_ABI=1 -fno-omit-frame-pointer  -fPIE -std=c++11 -o CMakeFiles/cmTC_cfc86.dir/check_tls_opts_132.cc.o -c /home/antoine/arrow/dev/cpp/src/arrow/flight/try_compile/check_tls_opts_132.cc
/home/antoine/arrow/dev/cpp/src/arrow/flight/try_compile/check_tls_opts_132.cc:28:31: error: 'TlsCredentialsOptions' in namespace 'grpc::experimental' does not name a type; did you mean 'AltsCredentialsOptions'?
   28 |     const grpc::experimental::TlsCredentialsOptions* options) {
      |                               ^~~~~~~~~~~~~~~~~~~~~
      |                               AltsCredentialsOptions
/home/antoine/arrow/dev/cpp/src/arrow/flight/try_compile/check_tls_opts_132.cc: In function 'grpc_tls_server_verification_option check(const int*)':
/home/antoine/arrow/dev/cpp/src/arrow/flight/try_compile/check_tls_opts_132.cc:29:61: error: request for member 'server_verification_option' in '* options', which is of non-class type 'const int'
   29 |   grpc_tls_server_verification_option server_opt = options->server_verification_option();
      |                                                             ^~~~~~~~~~~~~~~~~~~~~~~~~~
ninja: build stopped: subcommand failed.

There are two problems:

1. this is displayed as an error, but it's not an actual error from the user's point of view (Arrow builds fine nevertheless)
2. this is displayed each time when building, even if nothing needs rebuilding

Reporter: Antoine Pitrou / @pitrou
Assignee: David Li / @lidavidm

PRs and other links:

• GitHub Pull Request #8442

_{Note: This issue was originally created as ARROW-10286. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
cc @lidavidm @jduo

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 8442
#8442