Output configured NGenConfig header into build directories instead of include directory

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Relevant function call:

ngen/CMakeLists.txt

Line 350 in f57fec0

configure_file("${NGEN_INC_DIR}/NGenConfig.h.in" "${NGEN_INC_DIR}/NGenConfig.h")

Current behavior

Currently, this configure_file call outputs NGenConfig.h into the include/ directory alongside its template. However, this leads to issues in successive out-of-source builds, i.e. CIROH-UA/NGIAB-CloudInfra#50.

Expected behavior

Output and include the configured header to/from the user-specified build directory, so that each out-of-source build has its own NGenConfig.h. (using PROJECT_BINARY_DIR?)

Steps to replicate behavior (include URLs)

git clone https://github.com/NOAA-OWP/ngen.git
cd ngen
cmake -B build_dir_A -S . -DNGEN_WITH_MPI=OFF -DNGEN_WITH_PYTHON=OFF -DNGEN_WITH_TESTS=OFF
cmake -B build_dir_B -S . -DNGEN_WITH_MPI=ON -DNGEN_WITH_PYTHON=OFF -DNGEN_WITH_TESTS=OFF

cat include/NGenConfig.h
#> // NGenConfig.h
#> ...
#> #define NGEN_WITH_MPI 1
#> ...

# Will fail since `build_dir_A` was configured with NGEN_WITH_MPI=OFF, but
# the second configure caused `NGenConfig.h` to have `NGEN_WITH_MPI=ON`.
cmake --build build_dir_A -t ngen
#> ...
#> /ngen/src/NGen.cpp: In function ‘void ngen::exec_info::runtime_summary(std::ostream&)’:
#> /ngen/src/NGen.cpp:67:31: error: ‘mpi_rank’ was not declared in this scope
#>    67 |            << "    Rank: " << mpi_rank << "\n"
#>       |                               ^~~~~~~~
#> /ngen/src/NGen.cpp:68:37: error: ‘mpi_num_procs’ was not declared in this scope
#>    68 |            << "    Processors: " << mpi_num_procs << "\n";
#>       |                                     ^~~~~~~~~~~~~
#> /ngen/src/NGen.cpp: In function ‘int main(int, char**)’:
#> /ngen/src/NGen.cpp:136:9: error: ‘MPI_Init’ was not declared in this scope
#>   136 |         MPI_Init(nullptr, nullptr);
#>       |         ^~~~~~~~
#> /ngen/src/NGen.cpp:137:23: error: ‘MPI_COMM_WORLD’ was not declared in this scope
#>   137 |         MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
#>       |                       ^~~~~~~~~~~~~~
#> /ngen/src/NGen.cpp:137:40: error: ‘mpi_rank’ was not declared in this scope
#>   137 |         MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
#>       |                                        ^~~~~~~~
#> /ngen/src/NGen.cpp:137:9: error: ‘MPI_Comm_rank’ was not declared in this scope
#>   137 |         MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
#>       |         ^~~~~~~~~~~~~
#> /ngen/src/NGen.cpp:138:40: error: ‘mpi_num_procs’ was not declared in this scope
#>   138 |         MPI_Comm_size(MPI_COMM_WORLD, &mpi_num_procs);
#>       |                                        ^~~~~~~~~~~~~
#> /ngen/src/NGen.cpp:138:9: error: ‘MPI_Comm_size’ was not declared in this scope
#>   138 |         MPI_Comm_size(MPI_COMM_WORLD, &mpi_num_procs);
#>       |         ^~~~~~~~~~~~~
#> /ngen/src/NGen.cpp:149:9: error: ‘MPI_Finalize’ was not declared in this scope
#>   149 |         MPI_Finalize();
#>       |         ^~~~~~~~~~~~
#> make[3]: *** [CMakeFiles/ngen.dir/build.make:76: CMakeFiles/ngen.dir/src/NGen.cpp.o] Error 1
#> make[2]: *** [CMakeFiles/Makefile2:307: CMakeFiles/ngen.dir/all] Error 2
#> make[1]: *** [CMakeFiles/Makefile2:314: CMakeFiles/ngen.dir/rule] Error 2
#> make: *** [Makefile:125: ngen] Error 2

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Just noticed that this affects https://github.com/NOAA-OWP/ngen/blob/master/src/core/NGen_Python_Build_Versions.in as well if the user's python environment changes (i.e. switches virtual environments between configurations) -- probably will not be as common of an issue, but still something to consider.

[PhilMiller]

Do you want to lump that into the existing PR 682, or address it separately?

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Do you want to lump that into the existing PR 682, or address it separately?

I think I can lump this in real quick, should be pushed up relatively soon

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Addressed in 5c0bd8e.