Python: tighten up CMake configuration in attempt to get working cond…

…a builds for Linux, macOS, and Windows

CMakeLists.txt

@@ -1,5 +1,6 @@
-# CMake 3.15+ needed for SWIG version 4.0+ support.
-cmake_minimum_required(VERSION 3.15)
+# CMake 3.15+ needed for SWIG version 4.0+ support. 3.18+ needed for Development.Module
+# sub-component support for FindPyton.
+cmake_minimum_required(VERSION 3.18)
 project(OpenNavSurf-BAG LANGUAGES C CXX VERSION 2.0.1)
 set(CMAKE_CXX_STANDARD 14)
 

api/swig/python/CMakeLists.txt

@@ -5,11 +5,10 @@ cmake_policy(SET CMP0086 NEW)
 
 if(Python_LOOKUP_VERSION)
  set(Python_FIND_STRATEGY VERSION)
- find_package(Python ${Python_LOOKUP_VERSION} COMPONENTS Interpreter Development)
+ find_package(Python3 ${Python_LOOKUP_VERSION} COMPONENTS Interpreter Development.Module)
 else()
  set(Python_FIND_STRATEGY LOCATION)
- find_package(Python3 COMPONENTS Interpreter Development)
- set(Python_LIBRARIES Python3::Python)
+ find_package(Python3 COMPONENTS Interpreter Development.Module)
 endif()
 
 # Handle where to install the resulting Python package
@@ -23,8 +22,8 @@ else()
  set(BAGPY_INSTALL_PREFIX ${Python3_SITELIB})
 endif()
 
-if(DEFINED Python_INCLUDE_DIRS)
- include_directories("${CMAKE_SOURCE_DIR}/api" "${Python_INCLUDE_DIRS}")
+if(DEFINED Python3_INCLUDE_DIRS)
+ include_directories("${CMAKE_SOURCE_DIR}/api" "${Python3_INCLUDE_DIRS}")
 else()
  include_directories("${CMAKE_SOURCE_DIR}/api")
 endif()
@@ -52,8 +51,8 @@ set_target_properties(bagPy
 )
 
 target_link_libraries(bagPy
- ${Python_LIBRARIES}
- baglib
+ PRIVATE baglib
+ PRIVATE Python3::Module
 )
 
 if(${CMAKE_SYSTEM_NAME} MATCHES Darwin)

docs/BUILDING.md

@@ -31,7 +31,7 @@ This will generate an HTML coverage report in `build/ccov/all-merged/index.html`
 
 #### Build Python wheel
 After building the C++ library in the `build` directory as above, 
-you will be able to build a Python wheel as follows:
+you will be able to build a Python wheel for installing `bagPy` as follows:
 ```shell
 $ python -m pip wheel -w ./wheel/ ./build/api/swig/python
 ```
@@ -170,8 +170,8 @@ cmake --install build
 ```
 
 #### Build Python wheels:
-After building the C++ code, you can build a Python wheel of the `bagPy`
-bindings as follows:
+After building the C++ library in the `build` directory as above,
+you will be able to build a Python wheel for installing `bagPy` as follows:
  ```
 python -m pip wheel -w .\wheel\ .\build\api\swig\python
  ```