BLD: unvendor meson-python [wheel build]

The meson-python 0.15.0 release added the ability to configure a
custom `meson` in `pyproject.toml`. So there's no longer a need for
us to vendor it.

.gitmodules

@@ -10,6 +10,3 @@
 [submodule "vendored-meson/meson"]
 	path = vendored-meson/meson
 	url = https://github.com/numpy/meson.git
-[submodule "vendored-meson/meson-python"]
-	path = vendored-meson/meson-python
-	url = https://github.com/numpy/meson-python.git

LICENSES_bundled.txt

@@ -25,11 +25,6 @@ Files: vendored-meson/meson/*
 License: Apache 2.0
   For license text, see vendored-meson/meson/COPYING
 
-Name: meson-python
-Files: vendored-meson/meson-python/*
-License: MIT
-  For license text, see vendored-meson/meson-python/LICENSE
-
 Name: spin
 Files: .spin/cmds.py
 License: BSD-3

pyproject.toml

@@ -1,18 +1,8 @@
 [build-system]
 build-backend = "mesonpy"
-backend-path = ['./vendored-meson/meson-python']
 requires = [
+    "meson-python>=0.15.0",
     "Cython>=3.0",
-    # All dependencies of the vendored meson-python (except for meson, because
-    # we've got that vendored too - that's the point of this exercise).
-    'pyproject-metadata >= 0.7.1',
-    'tomli >= 1.0.0; python_version < "3.11"',
-    'setuptools >= 60.0; python_version >= "3.12"',
-    'colorama; os_name == "nt"',
-    # Note that `ninja` and (on Linux) `patchelf` are added dynamically by
-    # meson-python if those tools are not already present on the system. No
-    # need to worry about those unless one does a non-isolated build - in that
-    # case they must already be installed on the system.
 ]
 
 [project]
@@ -190,6 +180,9 @@ environment = {PKG_CONFIG_PATH="/opt/32/lib/pkgconfig"}
 config-settings = "setup-args=--vsenv setup-args=-Dallow-noblas=true"
 repair-wheel-command = ""
 
+[tool.meson-python]
+meson = 'vendored-meson/meson/meson.py'
+
 [tool.spin]
 package = 'numpy'