Use CPM and simplify CMake. (#2267)

There. I finally cracked. While trying to get CMake to play ball with
Tracy I had to devise the next
bespoke solution for adding a dependency. Now, we are just using CPM
https://github.com/cpm-cmake/CPM.cmake
which makes things significantly less painful, if not painless, it's
still CMake after all.

This means:
- No more submodules. Everything is pulled in via CPM.
- No more toggling between system packages and submodules. System is
preferred, if compatible.
- No more ten ways of adding a dependency. It's two now. (I'd prefer
one, but what can we do?)
- Significantly less code in our build system.

.github/workflows/benchmarks.yml

@@ -44,7 +44,7 @@ jobs:
         run: |
           mkdir build
           cd build
-          cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_MPI=OFF -DARB_USE_BUNDLED_LIBS=ON
+          cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_MPI=OFF
           ninja -j4 ubenches
           cd -
       - name: Run benchmarks

.github/workflows/codeql.yml

@@ -66,7 +66,7 @@ jobs:
       run: |
            mkdir build
            cd build
-           cmake .. -DCMAKE_CXX_COMPILER=g++ -DCMAKE_C_COMPILER=gcc -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=ON -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=OFF -DARB_USE_BUNDLED_LIBS=ON -DARB_WITH_ASSERTIONS=ON -DARB_WITH_PROFILING=ON
+           cmake .. -DCMAKE_CXX_COMPILER=g++ -DCMAKE_C_COMPILER=gcc -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=ON -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=OFF -DARB_WITH_ASSERTIONS=ON -DARB_WITH_PROFILING=ON
            make -j4 tests examples pyarb
            cd -
 

.github/workflows/sanitize.yml

@@ -61,7 +61,7 @@ jobs:
           mkdir build
           cd build
           export SAN="-fsanitize=${{ matrix.sanitizer }} -fno-omit-frame-pointer"
-          cmake .. -GNinja -DCMAKE_BUILD_TYPE=debug -DCMAKE_CXX_FLAGS="$SAN" -DCMAKE_C_FLAGS="$SAN" -DCMAKE_EXE_LINKER_FLAGS="$SAN" -DCMAKE_MODULE_LINKER_FLAGS="$SAN" -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_VECTORIZE=${{ matrix.simd }} -DARB_WITH_MPI=OFF -DARB_USE_BUNDLED_LIBS=ON -DARB_WITH_PYTHON=ON -DPython3_EXECUTABLE=`which python`
+          cmake .. -GNinja -DCMAKE_BUILD_TYPE=debug -DCMAKE_CXX_FLAGS="$SAN" -DCMAKE_C_FLAGS="$SAN" -DCMAKE_EXE_LINKER_FLAGS="$SAN" -DCMAKE_MODULE_LINKER_FLAGS="$SAN" -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_VECTORIZE=${{ matrix.simd }} -DARB_WITH_MPI=OFF -DARB_WITH_PYTHON=ON -DPython3_EXECUTABLE=`which python`
           ninja -j4 -v tests examples pyarb
           cd -
       - name: Run unit tests

.github/workflows/test-docs.yaml

@@ -37,5 +37,5 @@ jobs:
         run: |
           mkdir build
           cd build
-          cmake .. -DARB_WITH_PYTHON=ON -DPython3_EXECUTABLE=`which python` -DARB_USE_BUNDLED_LIBS=ON
+          cmake .. -DARB_WITH_PYTHON=ON -DPython3_EXECUTABLE=`which python`
           make html

.github/workflows/test-matrix.yml

@@ -153,7 +153,7 @@ jobs:
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
           mkdir build
           cd build
-          cmake .. -GNinja -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=${{ matrix.config.simd }} -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=${{ matrix.config.mpi }} -DARB_USE_BUNDLED_LIBS=ON -DARB_WITH_ASSERTIONS=ON -DARB_WITH_PROFILING=ON
+          cmake .. -GNinja -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=${{ matrix.config.simd }} -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=${{ matrix.config.mpi }} -DARB_WITH_ASSERTIONS=ON -DARB_WITH_PROFILING=ON
           ninja -j4 tests examples pyarb
           cd -
       - if:   ${{ matrix.variant == 'shared' }}
@@ -162,7 +162,7 @@ jobs:
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
           mkdir build
           cd build
-          cmake .. -GNinja -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=${{ matrix.config.simd }} -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=${{ matrix.config.mpi }} -DARB_USE_BUNDLED_LIBS=ON -DARB_WITH_ASSERTIONS=ON -DBUILD_SHARED_LIBS=ON -DARB_WITH_PROFILING=ON
+          cmake .. -GNinja -DCMAKE_CXX_COMPILER=$CXX -DCMAKE_C_COMPILER=$CC -DARB_WITH_PYTHON=ON -DARB_VECTORIZE=${{ matrix.config.simd }} -DPython3_EXECUTABLE=`which python` -DARB_WITH_MPI=${{ matrix.config.mpi }} -DARB_WITH_ASSERTIONS=ON -DBUILD_SHARED_LIBS=ON -DARB_WITH_PROFILING=ON
           ninja -j4 tests examples pyarb
           cd -
       - name: Install arbor

.github/workflows/test-pip.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Build and install Arbor using pip + build flags
         run: |
           source ~/env/bin/activate
-          CMAKE_ARGS="-DARB_VECTORIZE=ON -DARB_ARCH=native" pip install .
+          CMAKE_ARGS="-DARB_VECTORIZE=ON -DARB_ARCH=native" pip -vvv install .
       - name: Check that build flags match
         run: |
           source ~/env/bin/activate

.gitmodules

@@ -1,31 +0,0 @@
-[submodule "google-benchmark"]
-	path = ext/google-benchmark
-	url = https://github.com/google/benchmark.git
-	branch = main
-[submodule "ext/fmt"]
-	path = ext/fmt
-	url = https://github.com/fmtlib/fmt.git
-	branch = master
-[submodule "ext/random123"]
-	path = ext/random123
-	url = https://github.com/DEShawResearch/random123.git
-	branch = main
-[submodule "ext/json"]
-	path = ext/json
-	url = https://github.com/nlohmann/json.git
-	branch = master
-[submodule "ext/pybind11"]
-	path = ext/pybind11
-	url = https://github.com/pybind/pybind11.git
-	branch = master
-[submodule "ext/googletest"]
-	path = ext/googletest
-	url = https://github.com/google/googletest.git	
-	branch = main
-[submodule "ext/pugixml"]
-	path = ext/pugixml
-	url = https://github.com/zeux/pugixml.git
-	branch = master
-[submodule "ext/units"]
-	path = ext/units
-	url = https://github.com/LLNL/units.git

.gitpod.yml

@@ -11,7 +11,7 @@ tasks:
       mkdir build
       cmake -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -H/workspace/arbor -B/workspace/arbor/build \
       -DCMAKE_INSTALL_PREFIX:STRING=/workspace/arbor/install -DCMAKE_BUILD_TYPE:STRING=Debug -G "Unix Makefiles" \
-      -DARB_WITH_PYTHON:BOOL=ON -DARB_USE_BUNDLED_LIBS:BOOL=ON
+      -DARB_WITH_PYTHON:BOOL=ON
       ln -s /workspace/arbor/build/compile_commands.json /workspace/arbor
       export PYTHONPATH=/workspace/arbor/install/lib/python3.7/site-packages
     prebuild: |