MINOR: [C++] Bump bundled mimalloc version

[pitrou]

No description provided.

[pitrou]

Ok, we'll first have to bump our minimum CMake version because mimalloc now requires CMake 3.18:

-- stderr output is:
CMake Error at CMakeLists.txt:1 (cmake_minimum_required):
  CMake 3.18 or higher is required.  You are running version 3.16.3

[kou]

I don't object bumping our minimum CMake version but we can require CMake 3.18 or later only for mimalloc like we did for Azure SDK for C++:

arrow/cpp/cmake_modules/ThirdpartyToolchain.cmake

Lines 5421 to 5430 in 2b5a802

	if(CMAKE_VERSION VERSION_LESS 3.22)
	# We can't disable installing Azure SDK for C++ by
	# "set_property(DIRECTORY ${azure_sdk_SOURCE_DIR} PROPERTY
	# EXCLUDE_FROM_ALL TRUE)" with CMake 3.16.
	#
	# At least CMake 3.22 on Ubuntu 22.04 works. So we use 3.22
	# here. We may be able to use more earlier version here.
	message(FATAL_ERROR "Building Azure SDK for C++ requires at least CMake 3.22. "
	"(At least we can't use CMake 3.16)")
	endif()

[pitrou]

I don't object bumping our minimum CMake version but we can require CMake 3.18 or later only for mimalloc like we did for Azure SDK for C++:

We can do that, but mimalloc is our default allocator, so perhaps we want to bump the CMake version unconditionally. Is there a ML thread about this already? cc @assignUser

[assignUser]

I think the cmake discussion mostly happened in zulip.

[pitrou]

Closing in favor of #45979