Re-enable subinterpreters in iOS

Author: b-pass

include/pybind11/detail/common.h

@@ -256,7 +256,7 @@
 
 // Slightly faster code paths are available when PYBIND11_HAS_SUBINTERPRETER_SUPPORT is *not*
 // defined, so avoid defining it for implementations that do not support subinterpreters. However,
-// defining it unnecessarily is not expected to break anything (other than old iOS targets).
+// defining it unnecessarily is not expected to break anything.
 // This can be overridden by the user with -DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=1 or 0
 #ifndef PYBIND11_HAS_SUBINTERPRETER_SUPPORT
 #    if PY_VERSION_HEX >= 0x030C0000 && !defined(PYPY_VERSION) && !defined(GRAALVM_PYTHON)

tests/pyproject.toml

@@ -33,4 +33,4 @@ pyodide.test-groups = ["numpy", "scipy"]
 ios.test-groups = ["numpy"]
 ios.xbuild-tools = ["cmake", "ninja"]
 ios.environment.PIP_EXTRA_INDEX_URL = "https://pypi.anaconda.org/beeware/simple"
-ios.config-settings."cmake.define.CMAKE_CXX_FLAGS" = "-DPYBIND11_HAS_SUBINTERPRETER_SUPPORT=0"
+