Deploy and configure c/odbc macos worker and builder

Host configuration:

• latest macOS with xcode command line tools (latest clang)
• apple silicon host

  % brew list --formula --versions | grep -E "cmake|openssl|iodbc|zstd"

  cmake 4.2.3

  libiodbc 3.52.16

  openssl@3 3.6.1

  zstd 1.5.7_1

  % clang --version

  Apple clang version 17.0.0 (clang-1700.6.4.2)

  Target: arm64-apple-darwin25.2.0

Builder configuration:

• as per old-bb factory: https://buildbot.mariadb.net/buildbot/builders/codbc-macos

Use unix makefiles as a generator to avoid a full Xcode IDE configuration (requires an Apple Developer ID):

cmake . \

  -DCMAKE_BUILD_TYPE=RelWithDebInfo \

  -DWITH_SSL=OPENSSL \

  -DWITH_SIGNCODE=OFF \

  -DCONC_WITH_UNIT_TESTS=OFF \

  -DODBC_INCLUDE_DIR=/opt/homebrew/opt/libiodbc/include \

  -DODBC_LIB_DIR=/opt/homebrew/opt/libiodbc/lib \

  -DWITH_EXTERNAL_ZLIB=ON \