I have a simple c++23 module project which fails on CI, but not on my local host:
/opt/homebrew/opt/llvm/bin/../include/c++/v1/__locale_dir/support/bsd_like.h:21:10: fatal error: 'time.h' file not found
==> Upgrading cmake
3.31.6 -> 4.0.3
==> Pouring cmake--4.0.3.arm64_sequoia.bottle.tar.gz
Run export hostSystemName=Darwin
Darwin
Executing workflow step 1 of 4: configure preset "dev"
-- The CXX compiler identification is Clang 20.1.7
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /opt/homebrew/opt/llvm/bin/clang++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
'brew' '--prefix' 'llvm@20'
-- LLVM_ROOT=/opt/homebrew/Cellar/llvm/20.1.7
-- ALGO_USE_MODULES=TRUE
-- CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES=/opt/homebrew/Cellar/llvm/20.1.7/include/c++/v1;/opt/homebrew/Cellar/llvm/20.1.7/lib/clang/20/include;/Library/Developer/CommandLineTools/SDKs/MacOSX15.sdk/usr/include
-- Performing Test COMPILER_HAS_HIDDEN_VISIBILITY
-- Performing Test COMPILER_HAS_HIDDEN_VISIBILITY - Success
-- Performing Test COMPILER_HAS_HIDDEN_INLINE_VISIBILITY
-- Performing Test COMPILER_HAS_HIDDEN_INLINE_VISIBILITY - Success
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR
-- Performing Test COMPILER_HAS_DEPRECATED_ATTR - Success
CMake Warning (dev) at example/CMakeLists.txt:34 (add_test):
uninitialized variable 'CMAKE_TOOLCHAIN_FILE'
This warning is for project developers. Use -Wno-dev to suppress it.
-- Configuring done (2.8s)
CMake Warning:
-- Generating done (0.0s)
Manually-specified variables were not used by the project:
-- Build files have been written to: /Users/runner/work/cmake-init-modules/cmake-init-modules/build/dev
BUILD_MCSS_DOCS
Executing workflow step 2 of 4: build preset "dev"
cmake-init-modules_DEVELOPER_MODE
[1/11] Building CXX object CMakeFiles/Algo_verify_interface_header_sets.dir/Algo_verify_interface_header_sets/algo_export.h.cxx.o
[2/11] Scanning /Users/runner/work/cmake-init-modules/cmake-init-modules/example/main.cpp for CXX dependencies
[3/11] Scanning /Users/runner/work/cmake-init-modules/cmake-init-modules/algo-interface.cppm for CXX dependencies
[4/11] Scanning /Users/runner/work/cmake-init-modules/cmake-init-modules/algo-impl.cpp for CXX dependencies
FAILED: CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi
"/opt/homebrew/Cellar/llvm/20.1.7/bin/clang-scan-deps" -format=p1689 -- /opt/homebrew/opt/llvm/bin/clang++ -DAlgo_EXPORTS -I/Users/runner/work/cmake-init-modules/cmake-init-modules/build/dev -isystem /opt/homebrew/Cellar/llvm/20.1.7/include -Wall -Wextra -Wpedantic -Wconversion -Wsign-conversion -Wcast-qual -Wformat=2 -Wundef -Werror=float-equal -Wshadow -Wcast-align -Wunused -Wnull-dereference -Wdouble-promotion -Wimplicit-fallthrough -Wextra-semi -Woverloaded-virtual -Wnon-virtual-dtor -Wold-style-cast -g -std=gnu++23 -arch arm64 -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -x c++ /Users/runner/work/cmake-init-modules/cmake-init-modules/algo-impl.cpp -c -o CMakeFiles/Algo.dir/algo-impl.cpp.o -resource-dir "/opt/homebrew/Cellar/llvm/20.1.7/lib/clang/20" -MT CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi -MD -MF CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi.d > CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi.tmp && mv CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi.tmp CMakeFiles/Algo.dir/algo-impl.cpp.o.ddi
Error while scanning dependencies for /Users/runner/work/cmake-init-modules/cmake-init-modules/algo-impl.cpp:
In file included from /Users/runner/work/cmake-init-modules/cmake-init-modules/algo-impl.cpp:3:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/print:46:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/format:202:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__format/container_adaptor.h:20:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__format/range_default_formatter.h:23:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__format/range_formatter.h:23:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__format/format_context.h:28:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__locale:17:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__locale_dir/locale_base_api.h:117:
In file included from /opt/homebrew/opt/llvm/bin/../include/c++/v1/__locale_dir/support/apple.h:18:
/opt/homebrew/opt/llvm/bin/../include/c++/v1/__locale_dir/support/bsd_like.h:21:10: fatal error: 'time.h' file not found
ninja: build stopped: subcommand failed.
Error: Process completed with exit code 1.