LDC 1.20.0

[kinke]

Glad to announce LDC 1.20:

* Based on D 2.090.1+.
* Codegen preparations (but druntime/Phobos support still 
lacking) for
   * iOS/tvOS/watchOS on AArch64
   * WASI (WebAssembly System Interface)
* Mac: support for embedding `pragma({lib,linkerDirective}, ...)` 
in object files, e.g., `pragma(linkerDirective, "-framework", 
"CoreFoundation");`.
* Linux: fix potential stack overflows in GC worker threads.
* CLI fix for options specified with 2 (not just 1) leading 
dashes, e.g., --lowmem.
* Support for data directives in DMD-style inline asm.
* Phobos fixes for soft-float targets.

Full release log and downloads: 
https://github.com/ldc-developers/ldc/releases/tag/v1.20.0

Thanks to all contributors!