Provide a clang-compiled version of libdb2.dylib on macOS

[pavelzw]

Downloading and extracting https://github.com/ibmdb/db2drivers/blob/main/clidriver/macos64_odbc_cli.tar.gz and executing the following:

❯ otool -L clidriver/lib/libdb2.dylib
clidriver/lib/libdb2.dylib:
	libdb2.dylib (compatibility version 0.0.0, current version 0.0.0)
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1677.104.0)
	/System/Library/Frameworks/IOKit.framework/Versions/A/IOKit (compatibility version 1.0.0, current version 275.0.0)
	/usr/lib/libresolv.9.dylib (compatibility version 1.0.0, current version 1.0.0)
	/usr/local/lib/gcc/8/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.25.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1281.100.1)
	/usr/local/lib/gcc/8/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)

A large part of the macOS ecosystem relies on clang being used for compiling packages.
For example, when building the python bindings from source (and very small patches of https://github.com/ibmdb/python-ibmdb/blob/master/ibm_db.c) leads to the compilation working but during runtime I get the following issue:

import: 'ibm_db'
Traceback (most recent call last):
  File "/Users/runner/miniforge3/conda-bld/ibm_db_1722957211176/test_tmp/run_test.py", line 2, in <module>
    import ibm_db
ImportError: dlopen(.../lib/python3.11/site-packages/ibm_db.cpython-311-darwin.so, 0x0002): Symbol not found: (__ZNKSt8__detail20_Prime_rehash_policy14_M_need_rehashEmmm)
  Referenced from: '.../lib/python3.11/site-packages/clidriver/lib/libdb2.dylib'
  Expected in: '/usr/lib/libstdc++.6.dylib'

It would help a lot if there was a libdb2.dylib available that is build with clang from macOS.
I know that installing GCC via homebrew would solve this issue but this is not an option for me.