CMake: generate panda3d.dist-info directory

This makes pip recognise that Panda3D has been installed and setuptools recognise the build_apps and bdist_apps commands.

cmake/templates/METADATA.in

@@ -0,0 +1,7 @@
+Metadata-Version: 2.0
+Name: Panda3D
+Version: ${PROJECT_VERSION}
+License: BSD
+Home-page: https://www.panda3d.org/
+Author: Panda3D Team
+Author-email: [email protected]

panda/CMakeLists.txt

@@ -145,6 +145,16 @@ from .interrogatedb import *
     file(WRITE "${PROJECT_BINARY_DIR}/panda3d/dtoolconfig.py" ${dtoolconfig_file})
   endif()
 
+  # Also generate a panda3d.dist-info directory.
+  set(entry_points_file "[distutils.commands]
+build_apps = direct.dist.commands:build_apps
+bdist_apps = direct.dist.commands:bdist_apps
+")
+
+  configure_file("${PROJECT_SOURCE_DIR}/cmake/templates/METADATA.in"
+                 "${PROJECT_BINARY_DIR}/panda3d.dist-info/METADATA")
+  file(WRITE "${PROJECT_BINARY_DIR}/panda3d.dist-info/entry_points.txt" ${entry_points_file})
+
   if(HAVE_BULLET)
     add_python_module(panda3d.bullet p3bullet IMPORT panda3d.core COMPONENT BulletPython)