feat: use custom search path and normal pip package

CMakeLists.txt

-cmake_minimum_required(VERSION 3.7...3.18)
+cmake_minimum_required(VERSION 3.18)
 
 project(scikit_build_example VERSION "0.0.1")
 
 # Define CMAKE_INSTALL_xxx: LIBDIR, INCLUDEDIR
 include(GNUInstallDirs)
 
+# Currently, Scikit-build does not support FindPython, so we convert the
+# provided hints ourselves.
+if(SKBUILD)
+  set(Python_EXECUTABLE "${PYTHON_EXECUTABLE}")
+  set(Python_INCLUDE_DIR "${PYTHON_INCLUDE_DIR}")
+  set(Python_LIBRARY "${PYTHON_LIBRARY}")
+endif()
+
+set(Python_FIND_IMPLEMENTATIONS CPython PyPy)
+find_package(Python REQUIRED COMPONENTS Interpreter Development)
+
+# Scikit-Build does not add your site-packages to the search path automatically,
+# so we need to add it here.
+execute_process(
+  COMMAND
+    "${Python_EXECUTABLE}" -c
+    "import skbuild, os; print(os.path.dirname(os.path.dirname(skbuild.__file__)))"
+  OUTPUT_VARIABLE _tmp_sitepackages
+  OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ECHO STDOUT ECHO_OUTPUT_VARIABLE
+  ECHO_ERROR_VARIABLE)
+list(APPEND CMAKE_PREFIX_PATH "${_tmp_sitepackages}")
+
+# Now we can find pybind11
 find_package(pybind11 CONFIG REQUIRED)
 
 pybind11_add_module(_core MODULE src/main.cpp)
@@ -12,6 +35,3 @@ pybind11_add_module(_core MODULE src/main.cpp)
 target_compile_definitions(_core PRIVATE VERSION_INFO=${PROJECT_VERSION})
 
 install(TARGETS _core DESTINATION .)
-
-# Quiet a warning, since this project is only valid with SKBUILD
-set(ignoreMe "${SKBUILD}")

pyproject.toml

@@ -2,7 +2,7 @@
 requires = [
     "setuptools>=42",
     "wheel",
-    "pybind11-global",
+    "pybind11==2.6.0.dev1",
     "cmake",
     "scikit-build",
 ]