The most common solution is to just set CMAKE_PREFIX_PATH to /opt/homebrew. CMake will then look preferentially in /opt/homebrew for everything. Since you're on Apple, you might need to set CMAKE_FIND_FRAMEWORK and CMAKE_FIND_APPBUNDLE to LAST or NEVER, too.
You can skip the standard platform search paths by setting CMAKE_FIND_USE_CMAKE_SYSTEM_PATH to FALSE at the command line, in a preset, or in a toolchain file. You might also wish to disable looking at the PATH environment variable by setting CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH to FALSE.
Finally, if you're in a cross-compiling scenario or toolchain file, you can change the definition of the system directories by setting CMAKE_SYSROOT. Note that the sysroot will have to contain the language runtime libraries (e.g. glibc) and will be passed to the --sysroot flag (or equivalent). Just be aware of those effects, too.
All of this is documented here:
The following homebrew.cmake toolchain file worked for me:
set(HOMEBREW_PREFIX "/usr/local"
CACHE PATH "Path to Homebrew installation")
set(CMAKE_C_COMPILER "${HOMEBREW_PREFIX}/bin/gcc-11")
set(CMAKE_CXX_COMPILER "${HOMEBREW_PREFIX}/bin/g++-11")
set(CMAKE_PREFIX_PATH
"${HOMEBREW_PREFIX}"
# These libraries are keg-only and not loaded into
# the root prefix by default (to avoid clashes).
"${HOMEBREW_PREFIX}/opt/lapack"
"${HOMEBREW_PREFIX}/opt/openblas"
"${HOMEBREW_PREFIX}/opt/gcc/lib/gcc/11"
)
list(TRANSFORM CMAKE_PREFIX_PATH APPEND "/include"
OUTPUT_VARIABLE CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES)
set(CMAKE_C_STANDARD_INCLUDE_DIRECTORIES "${CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES}")
set(CMAKE_FIND_FRAMEWORK NEVER)
set(CMAKE_FIND_APPBUNDLE NEVER)
set(CMAKE_FIND_USE_CMAKE_SYSTEM_PATH FALSE)
set(CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH FALSE)
I built with the following commands:
$ ls
tRecX homebrew.cmake
$ cmake -G Ninja -S tRecX -B tRecX-build \
-DCMAKE_TOOLCHAIN_FILE=$PWD/homebrew.cmake \
-DCBLAS=/usr/local/opt/openblas/lib/libblas.dylib \
-DCMAKE_EXE_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_SHARED_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_BUILD_TYPE=Parallel
[ ... output clipped ... ]
Boost found -- full functionality
Build "Parallel" with C++ flags -D_USE_BOOST_ -O3 -pthread -D_USE_FFTW_, return to default by -UCMAKE_BUILD_TYPE
Compiler: /usr/local/bin/g++-11, change by -DCMAKE_CXX_COMPILER=[path_to_complier]
-- Linking to libraries Boost::system;Boost::filesystem;/usr/local/lib/libfftw3.dylib;/usr/local/opt/gcc/lib/gcc/11/libgfortran.dylib;alglib;/usr/local/lib/libarpack.dylib;Boost::system;Boost::filesystem;/usr/local/opt/lapack/lib/liblapacke.dylib;/usr/local/opt/openblas/lib/libblas.dylib;/usr/local/opt/lapack/lib/liblapack.dylib;/usr/local/opt/lapack/lib/libblas.dylib;m
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/alexreinking/Development/tRecX-build
$ cmake --build tRecX-build
I had to set CBLAS manually because libblas.dylib provides the OpenBLAS CBLAS interface, but the build system specifically looks for a library named libcblas. There's no other option in this case.
The code and build have issues with its linking model and dependencies. I was able to paper over these by setting -Wl,-undefined,dynamic_lookup. However, note that this will just defer linker errors to runtime and might impose a large startup cost.
If you can make commits to the project, I would store these settings in a preset, maybe name it homebrew-parallel or something:
-DCMAKE_TOOLCHAIN_FILE=$PWD/homebrew.cmake \
-DCBLAS=/usr/local/opt/openblas/lib/libblas.dylib \
-DCMAKE_EXE_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_SHARED_LINKER_FLAGS="-Wl,-undefined,dynamic_lookup" \
-DCMAKE_BUILD_TYPE=Parallel
Then you could just run cmake --preset=homebrew-parallel
