LDC 1.38.0-beta1

[kinke]

Glad to announce the first beta for LDC 1.38. Major changes:

* Based on D 2.108.0+ (yesterday's DMD stable).
* Support for LLVM 18; the prebuilt packages use v18.1.3.
* Android: Switch to native ELF TLS, supported since API level 29 
(Android v10), dropping our former custom TLS emulation 
(requiring a modified LLVM and a legacy ld.bfd linker). The 
prebuilt packages themselves require Android v10+ (armv7a) / v11+ 
(aarch64) too, and are built with NDK r26d. Shared druntime and 
Phobos libraries are now available (`-link-defaultlib-shared`), 
as on regular Linux.

Full release log and downloads: 
https://github.com/ldc-developers/ldc/releases/tag/v1.38.0-beta1

Please help test, and thanks to all contributors & sponsors!