Fix cmake build on macOS with hdf5 1.13.0 and cmake 3.17.2

[5tefan]

Resolved 2 Issue preventing CMake netcdf-cxx4 build on MacOS.

Trying to build latest HDF5, NetCDF-c, and then NetCDF-cxx4 from source on macOS Mojave using cmake version 3.17.2, hdf5 1.13.0 at 88a39adaa, and netcdf-c 4.8.0 at c2ea69df.

With NetCDF-cxx4, first issue:

mkdir build && cd build
cmake -DCMAKE_BUILD_TYPE=Release -DHDF5_DIR=/usr/local/HDF_Group/HDF5/1.13.0/share/cmake/hdf5/ ..

[...]
-- Found HDF5: hdf5-shared (found version "1.13.0") found components: C HL                                                                                           
CMake Error at CMakeLists.txt:415 (CHECK_LIBRARY_EXISTS):                         
  CHECK_LIBRARY_EXISTS Macro invoked with incorrect arguments for macro
  named: CHECK_LIBRARY_EXISTS                                                     

-- Plugin support requires libhdf5 with H5Free support. Your libhdf5 install does not provide H5Free.  Please install a newer version of libhdf5 if you require plugin compression support.
[...]
-- Configuring incomplete, errors occurred!  

Attributed to blank variable HDF5_C_LIBRARY_hdf5 in CMakeLists.txt. The FIND_PACKAGE(HDF5... call [1] sets HDF5_C_LIBRARIES. Looks like this snippet might have been copied from the NetCDF-c cmake, but the part that actually sets HDF5_C_LIBRARY_hdf5 from HDF5_C_LIBRARIES was omitted? Solution, modify HDF5_C_LIBRARY_hdf5 -> HDF5_C_LIBRARIES.

Build gets a little further, but gets stuck with error:

[...]
CMake Error in cxx4/CMakeLists.txt:
  Target "netcdf-cxx4" INTERFACE_INCLUDE_DIRECTORIES property contains path:

    "/full/path/to/netcdf-cxx4/cxx4/"

  which is prefixed in the source directory.

-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.

Using [2] [3]:

include(CMakePrintHelpers) # debug
cmake_print_properties(TARGETS netcdf-cxx4 PROPERTIES INTERFACE_INCLUDE_DIRECTORIES) # debug
variable_watch(HDF5_C_INCLUDE_DIRS) # debug
target_include_directories(netcdf-cxx4 SYSTEM PUBLIC "${HDF5_C_INCLUDE_DIRS}")
cmake_print_properties(TARGETS netcdf-cxx4 PROPERTIES INTERFACE_INCLUDE_DIRECTORIES) # debug

Finally tracked this down to the line above in cxx4/CMakeLists.txt referring to empty variable HDF5_C_INCLUDE_DIRS. Again FindHDF5 [1] sets HDF5_INCLUDE_DIRS, so changing HDF5_C_INCLUDE_DIRS -> HDF5_INCLUDE_DIRS seems to fix. Interestingly, compilation and tests pass even removing that line. Is that line necessary?

Thanks!

[1] https://cmake.org/cmake/help/v3.0/module/FindHDF5.html [2] https://cmake.org/cmake/help/latest/module/CMakePrintHelpers.html [3] https://cmake.org/cmake/help/latest/command/variable_watch.html

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[WardF]

Thanks!