Fixes to allow build artifacts

- Removed a delegating ctor which fails on macOS gcc with error "delegating constructors are
  permitted only in C++11".

- Add version to toml file, required by cibuildwheel (and pyproject.toml specification, I
  think) and have setup.py file extract it dynamically so we only have to maintain one.  I need
  to determine if the setup keywords are even required or if it will pick up items from the
  toml file.

.github/workflows/artifacts_build.yml

@@ -34,7 +34,6 @@ jobs:
         # https://docs.github.com/en/actions/using-jobs/choosing-the-runner-for-a-job
         # https://raw.githubusercontent.com/actions/python-versions/main/versions-manifest.json
         os: [windows-2019, macos-11, ubuntu-22.04]
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - uses: actions/checkout@v3

pyproject.toml

@@ -1,3 +1,38 @@
+[project]
+name = "pyodbc"
+version = "5.0.0a2"
+
+requires-python = ">=3.7"
+# This is used by the Github action that builds release artifacts using cibuildwheel.
+# cibuildwheel reads this directly:
+#
+# https://cibuildwheel.readthedocs.io/en/stable/options/#requires-python
+
+description = "DB API module for ODBC"
+readme = "README.md"
+license = {text = "MIT License"}
+
+authors = [{name = "Michael Kleehammer", email="[email protected]"}]
+
+maintainers = [{name = "Michael Kleehammer", email="[email protected]"}]
+# There are a lot of contributors and I'd like to include everyone that puts in a lot of
+# effort, but is this for the more technical meaning of who makes builds?  Would adding
+# contributors cause confusion.
+
+classifiers=['Development Status :: 5 - Production/Stable',
+             'Intended Audience :: Developers',
+             'Intended Audience :: System Administrators',
+             'License :: OSI Approved :: MIT License',
+             'Operating System :: Microsoft :: Windows',
+             'Operating System :: POSIX',
+             'Programming Language :: Python',
+             'Programming Language :: Python :: 3',
+             'Topic :: Database',
+             ]
+
+[project.urls]
+Homepage = "https://github.com/mkleehammer/pyodbc"
+
 [build-system]
 requires = ["setuptools"]
 build-backend = "setuptools.build_meta"

setup.py

@@ -1,14 +1,34 @@
 #!/usr/bin/env python
 
-import sys, os, shlex
+import sys, os, shlex, re
 from os.path import exists, join, isdir, relpath, expanduser
+from pathlib import Path
 from inspect import cleandoc
 
 from setuptools import setup
 from setuptools.extension import Extension
 
 
-VERSION = '5.0.0a1'
+def _getversion():
+    # CAREFUL: We need the version in this file so we can set it in a C macro to set
+    # pyodbc.__version__, plus the setup function might require it.  We also need it in the
+    # toml file or cibuildwheel will fail.  Instead of requiring a toml parser for older
+    # versions of Python, we'll parse it out with a regexp, which is very simple.
+    path = Path(__file__).parent / 'pyproject.toml'
+    assert path.exists(), f'Cannot find {path}'
+    text = path.read_text(encoding='utf8')
+    m = re.search(
+        r"""
+        ^ \s* version \s*=\s* "([^"]+)"
+        """,
+        text,
+        flags=re.VERBOSE | re.MULTILINE | re.IGNORECASE)
+    if not m:
+        sys.exit(f'Did not find version in {path}')
+    return m.group(1)
+
+
+VERSION = _getversion()
 
 
 def main():

src/textenc.h

@@ -84,8 +84,8 @@ class SQLWChar
     }
 
     SQLWChar(PyObject* src, const TextEnc* penc)
-        : SQLWChar(src, *penc)
     {
+        init(src, *penc);
     }
 
     SQLWChar(PyObject* src, const TextEnc& enc)