chore: drop toml, use tomli (#876)

This is required to get TOML 1.0 support, and lightens our dependencies a bit.

cibuildwheel/extra.py

@@ -2,22 +2,31 @@
 These are utilities for the `/bin` scripts, not for the `cibuildwheel` program.
 """
 
-from typing import Any, Dict
+from io import StringIO
+from typing import Dict, List
 
-import toml.encoder
-from packaging.version import Version
+from .typing import Protocol
+
+__all__ = ("Printable", "dump_python_configurations")
 
 
-class InlineArrayDictEncoder(toml.encoder.TomlEncoder):  # type: ignore
-    def __init__(self) -> None:
-        super().__init__()
-        self.dump_funcs[Version] = lambda v: f'"{v}"'
+class Printable(Protocol):
+    def __str__(self) -> str:
+        ...
 
-    def dump_sections(self, o: Dict[str, Any], sup: str) -> Any:
-        if not all(isinstance(a, list) for a in o.values()):
-            return super().dump_sections(o, sup)
-        val = ""
-        for k, v in o.items():
-            inner = ",\n  ".join(self.dump_inline_table(d_i).strip() for d_i in v)
-            val += f"{k} = [\n  {inner},\n]\n"
-        return val, self._dict()
+
+def dump_python_configurations(inp: Dict[str, Dict[str, List[Dict[str, Printable]]]]) -> str:
+    output = StringIO()
+    for header, values in inp.items():
+        output.write(f"[{header}]\n")
+        for inner_header, listing in values.items():
+            output.write(f"{inner_header} = [\n")
+            for item in listing:
+                output.write("  { ")
+                dict_contents = (f'{key} = "{value}"' for key, value in item.items())
+                output.write(", ".join(dict_contents))
+                output.write(" },\n")
+            output.write("]\n")
+        output.write("\n")
+    # Strip the final newline, to avoid two blank lines at the end.
+    return output.getvalue()[:-1]