revive UE toolchain build (#343)

* add comment about 7z usage in xmake bundle
* add ue-libcxx lib/headers and licence + tps
* update get_ue_toolchain.sh to use embedded libc++ and decouple from p4
* clearer output when falling back to zip from 7z
* update ci scripts to use ue toolchain on linux
* updated linux build README.md
* changelog

1 files changed, 19 insertions, 12 deletions

diff --git a/scripts/ue_build_linux/README.md b/scripts/ue_build_linux/README.md
index 00249ddbe..060f1a77a 100755
--- a/scripts/ue_build_linux/README.md
+++ b/scripts/ue_build_linux/README.md
@@ -2,31 +2,38 @@
 

 This folder contains scripts to build Zen using the UE Linux toolchain. This

 can be used to output binaries that meet the VFX Reference Platform versions.

-It works by using the --sysroot= option to redirect compilers and linkers to

+It works by using the `--sysroot=` option to redirect compilers and linkers to

 find headers and libraries. There are a few components involved;

 

 1) get_ue_toolchain.sh <toolchain_dir>

 

-This will download the required components from Perforce and structure them in

-such a way that they can be used by both vcpkg and xmake when building Zen.

+```

+$ scripts/ue_linux_build/get_ue_toolchain.sh ./.tmp-ue-toolchain

+```

+

+This will download the required components from cdn.unrealengine.com and

+structure them in such a way that they can be used by both vcpkg and xmake

+when building Zen.

 

 2) ue_build.sh <toolchain_dir> <prog> [args...] 

 

-Given the toolchain location downloaded in step (1), this script sets up a

-suitable environment and execs the "prog [args...]". It is expected that this

-is used to invoke xmake to build Zen;

+Given the toolchain location downloaded in step (1) and the `VCPKG_ROOT`

+environment variable is properly configured, this script sets up a suitable

+environment and execs the "prog [args...]".

+

+It is expected that this is used to invoke xmake to build Zen;

 

 ```

-$ scripts/ue_linux_build/ue_build.sh ~/uetools xmake config --mode=debug --vcpkg=~/vcpkg

-$ scripts/ue_linux_build/ue_build.sh ~/uetools xmake build

+$ scripts/ue_linux_build/ue_build.sh .tmp-ue-toolchain xmake config --mode=debug

+$ scripts/ue_linux_build/ue_build.sh .tmp-ue-toolchain xmake build

 ```

 

 It is possible that `--toolchain=clang` may be required as a configuration

-option. The ue_build.sh script can also be sourced into the current shell,

+option. The `ue_build.sh` script can also be sourced into the current shell,

 although it is worth noting that this has never been tried.

 

-3) clang / clang++

+3) `scripts/ue_build_linux/clang` / `scripts/ue_build_linux/clang++`

 

 These acts as shims to the binaries in `toolchain_dir`, adding in the required

-command line arguments to use the correct headers and libraries. The ue_build.sh

-script adjusts $PATH appropriately.

+command line arguments to use the correct headers and libraries.

+The `ue_build.sh` script adjusts `$PATH` appropriately.