ldb: 1.3.3 → 2.1.1

* Move build tools to nativeBuildInputs
* Switch to Python 3 as it is required by most Samba libraries
* Do not yet enable the experimental lmdb backend introduced in 1.4.0

Changes:
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=4e2eb5660a11cea215d39495844aa76ffb5a1a2e
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=3eecdbcc38dbe084b285c9720443d819304f7b97
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=b7f0ee93f58e663bb8fc0b39985aa49b254582d9
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=bdbb9422c0430d74c3173822257e23a9dfb2713e
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=340cb9ca97bc2a23f102f80897a8d8f4809f0072
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=de3bb5cd5236565f2b79644d99e55d03b254b65e
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=09d281d69b668a71e4457889bb5e949414a664fb
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=81648d576d56e924945b2214ac12ca6a40679db8
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=86d480ade25953a175b0837667ce5efb8b7e65df
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=80bd467affbda1d962f4deb3caa8a42c6531425d
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=bc0d16c9d8eacd254552ff28726a2ba5f2a1c8c0
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=c37b94fd0a7b24df93b664ad4c2d197c516c9dce
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=79460b1b9f3452d6d68014b84f4a9dc3988bd916
* https://git.samba.org/samba.git/?p=samba.git;a=commit;h=0ca46a37268c8219192abc3ab5f2546a02ed8862