Some issues with Gentoo

[skinkie]

I have had quite some issues getting this to work on Gentoo Linux and still trying to find out how to get this to work in a normal fashion.

1. Find without cmake .. -DQt5_DIR=/usr/lib64/cmake/Qt5 I cannot get the Qt5 stuff to work.
2. I had Python 3.8, 3.9, 3.10 installed, but only 3.8 and 3.9 had PySide2 available, I could not make CMake choose Python 3.9. (I unstalled 3.10, after which I found out it was not really the root cause)
3. The program assumes pyside2_config.py is available, this is not the case for Gentoo
4. I had to manually set the path to my shiboken2 binary
5. My Typesystems were added via -T/usr/share/PySide2/typesystems
6. Then I had to add `target_include_directories(${bindings_library} PRIVATE "/usr/include/shiboken2")
7. Then I had to add `target_include_directories(${bindings_library} PRIVATE "/usr/include/PySide2")
8. Then I had to add `target_include_directories(${bindings_library} PRIVATE "/usr/include/PySide2/QtCore")

Until this point it compiled, but when calling main.py, I received a particular error, a similar one with https://github.com/giumas/shiboken2_minimal

Traceback (most recent call last):
  File "/mnt/storage/home/skinkie/Sources/Example_Qt_and_Shiboken2/main.py", line 1, in <module>
    from Shiboken2QtExample import *
ImportError: /mnt/storage/home/skinkie/Sources/Example_Qt_and_Shiboken2/Shiboken2QtExample.so: undefined symbol: _ZN8Shiboken11Conversions22nonePythonToCppNullPtrEP7_objectPv

Eventually traced that back to;

1. shiboken_shared_libraries was not set, set(shiboken_shared_libraries shiboken2-python3.9)
2. pyside2_link was not set, set(pyside2_link pyside2-python3.9)

I documented these changes, but maybe something could be done to make the example more forgiving.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd6cc3f..d100ab3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,10 +52,13 @@ pyside2_config(--shiboken2-module-path shiboken2_module_path)
 pyside2_config(--shiboken2-generator-path shiboken2_generator_path)
 pyside2_config(--python-include-path python_include_dir)
 pyside2_config(--shiboken2-generator-include-path shiboken_include_dir 1)
-pyside2_config(--shiboken2-module-shared-libraries-cmake shiboken_shared_libraries 0)
-pyside2_config(--pyside2-shared-libraries-cmake pyside2_link 0)
+# pyside2_config(--shiboken2-module-shared-libraries-cmake shiboken_shared_libraries 0)
+# pyside2_config(--pyside2-shared-libraries-cmake pyside2_link 0)
 
-set(shiboken_path "${shiboken2_generator_path}/shiboken2${CMAKE_EXECUTABLE_SUFFIX}")
+set(shiboken_shared_libraries shiboken2-python3.9)
+set(pyside2_link pyside2-python3.9)
+
+set(shiboken_path "/usr/bin/shiboken2")
 if(NOT EXISTS ${shiboken_path})
     message(FATAL_ERROR "Shiboken executable not found at path: ${shiboken_path}")
 endif()
@@ -84,6 +87,7 @@ set(shiboken_options --generator-set=shiboken --enable-parent-ctor-heuristic
     ${lib_includes}
     -I${CMAKE_SOURCE_DIR}
     -T${CMAKE_SOURCE_DIR}
+    -T/usr/share/PySide2/typesystems
     -T${PYSIDE2_DIR}/typesystems/
     --output-directory=${CMAKE_CURRENT_BINARY_DIR}
     )
@@ -106,6 +110,12 @@ target_include_directories(${bindings_library} PRIVATE ${python_include_dir})
 target_include_directories(${bindings_library} PRIVATE ${PYSIDE2_DIR}/include/)
 target_include_directories(${bindings_library} PRIVATE ${PYSIDE2_DIR}/include/QtCore)
 target_include_directories(${bindings_library} PRIVATE ${shiboken_include_dir})
+target_include_directories(${bindings_library} PRIVATE
+    "/usr/include/shiboken2")
+target_include_directories(${bindings_library} PRIVATE
+    "/usr/include/PySide2")
+target_include_directories(${bindings_library} PRIVATE
+    "/usr/include/PySide2/QtCore")
 target_include_directories(${bindings_library} PRIVATE ${CMAKE_SOURCE_DIR})
 
 target_link_libraries(${bindings_library} PRIVATE ${shiboken_shared_libraries})