Changelog: Add v1.23 (#3542)

CHANGELOG.md

@@ -1,3 +1,32 @@
+# LDC 1.23.0 (2020-08-19)
+
+#### Big news
+- Frontend, druntime and Phobos are at version [2.093.1+](https://dlang.org/changelog/2.093.0.html), incl. new command-line option `-vtemplates`. (#3476, #3538, #3541)
+- Min required LLVM version raised to v6.0, dropping support for v3.9-5.0. (#3493)
+- LLVM for prebuilt packages bumped to v10.0.1. (#3513)
+- The prebuilt Mac package now also includes prebuilt druntime/Phobos for the iOS/x86_64 simulator, making cross-compilation work out of the box with `-mtriple=x86_64-apple-ios12.0`. (#3478)
+- Windows: New `-gdwarf` CLI option to emit DWARF debuginfos for MSVC targets, e.g., for debugging with gdb/lldb. (#3533)
+- New `-platformlib` CLI option to override the default linked-with platform libraries, e.g., when targeting bare-metal. (#3374, #3475)
+
+#### Platform support
+- Supports LLVM 6.0 - 10.0.
+
+#### Bug fixes
+- Fix regression since v1.22: shared druntime potentially overriding libstdc++ symbols and breaking exceptions in C++ libraries. (#3530, #3537)
+- Fix naked DMD-style asm emission for non-Mac x86 Darwin targets (e.g., iOS simulators). (#3478)
+- `-betterC`: Don't use unsupported EH for handling clean-ups. (#3479, #3482)
+- dcompute: Fix wrong address space loads and stores. Thx Rob! (#3428)
+- Fix ICE wrt. missing IR declarations for some forward-declared functions. (#3496, #3503)
+- Fix ICE wrt. inline IR and empty parameter types tuple. (#3509)
+- Fix PGO issues. (#3375, #3511, #3512, #3524)
+- Improve support for LLVM's ThreadSanitizer. (#3522)
+- Fix linker cmdline length limitation via response files. (#3535, #3536)
+
+#### Internals
+- Compiler performance wrt. string literals emission has been improved. Thx @looked-at-me! (#3490, #3492)
+- Link libstdc++ statically for `libldc-jit.so` of prebuilt Linux packages, to increase portability. (#3473, #3474)
+- Set up Visual D when using the Visual Studio CMake generator, making LDC compiler development on Windows a smooth out-of-the-box experience. (#3494)
+
 # LDC 1.22.0 (2020-06-16)
 
 #### Big news