fix(cmake): support vcpkg, try 2 (#4123)

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

tools/pybind11Tools.cmake

@@ -115,6 +115,7 @@ if(PYTHON_IS_DEBUG)
     PROPERTY INTERFACE_COMPILE_DEFINITIONS Py_DEBUG)
 endif()
 
+# The <3.11 code here does not support release/debug builds at the same time, like on vcpkg
 if(CMAKE_VERSION VERSION_LESS 3.11)
   set_property(
     TARGET pybind11::module
@@ -130,16 +131,19 @@ if(CMAKE_VERSION VERSION_LESS 3.11)
     APPEND
     PROPERTY INTERFACE_LINK_LIBRARIES pybind11::pybind11 $<BUILD_INTERFACE:${PYTHON_LIBRARIES}>)
 else()
+  # The IMPORTED INTERFACE library here is to ensure that "debug" and "release" get processed outside
+  # of a generator expression - https://gitlab.kitware.com/cmake/cmake/-/issues/18424, as they are
+  # target_link_library keywords rather than real libraries.
+  add_library(pybind11::_ClassicPythonLibraries IMPORTED INTERFACE)
+  target_link_libraries(pybind11::_ClassicPythonLibraries INTERFACE ${PYTHON_LIBRARIES})
   target_link_libraries(
     pybind11::module
     INTERFACE
       pybind11::python_link_helper
-      "$<$<OR:$<PLATFORM_ID:Windows>,$<PLATFORM_ID:Cygwin>>:$<BUILD_INTERFACE:${PYTHON_LIBRARIES}>>"
-  )
+      "$<$<OR:$<PLATFORM_ID:Windows>,$<PLATFORM_ID:Cygwin>>:pybind11::_ClassicPythonLibraries>")
 
   target_link_libraries(pybind11::embed INTERFACE pybind11::pybind11
-                                                  $<BUILD_INTERFACE:${PYTHON_LIBRARIES}>)
-
+                                                  pybind11::_ClassicPythonLibraries)
 endif()
 
 function(pybind11_extension name)