add docker target for windows_amd64 and update readme for cross-compiling

Author: SuburbanDad

.bazelrc

@@ -44,7 +44,7 @@ build:debug --verbose_failures
 build:debug -s
 
 # Docker Sandbox Mode - Note all docker sandbox configs must run from a linux x86_64 host
-build:docker-sandbox --experimental_docker_image=suburbandad/cross-clang-10:latest
+build:docker-sandbox --experimental_docker_image=suburbandad/prysm-cross:latest
 build:docker-sandbox --spawn_strategy=docker --strategy=Javac=docker --genrule_strategy=docker
 build:docker-sandbox --define=EXECUTOR=remote
 build:docker-sandbox --experimental_docker_verbose
@@ -100,3 +100,6 @@ build:windows_amd64 --compiler=mingw-w64
 build:windows_amd64_debug --config=windows_amd64
 build:windows_amd64_debug --config=debug
 
+# windows_amd64 docker sandbox build config
+build:windows_amd64_docker --config=windows_amd64_debug
+build:windows_amd64_docker --config=docker-sandbox

tools/cross-toolchain/README.md

@@ -1,4 +1,4 @@
-# WIP Multiarch Cross Compiling Toolchain
+# Multiarch Cross Compiling Toolchain
 
 ### Containerized Builds
 This project declares a c++ toolchain suite with cross compilers for targeting four platforms:
@@ -11,15 +11,15 @@ The toolchain suite describes cross compilers defined in a docker container desc
 
 
 ### Using Published Docker Container for Cross Compilation Targets:
-This is still a WIP, at the time of this writing linux_amd64, linux_arm64, and osx_amd64 are working targets.
+At the time of this writing linux_amd64, linux_arm64, osx_amd64, and windows_amd64 are working targets.
 
 #### If your host machine is linux_amd64
 If you are on linux_amd64 and you have docker configured, you can simply use bazel with the docker target configs.  See the table below
 
 #### Otherwise run the cross compiler image
 1. checkout prysm, `git clone https://github.com/prysmaticlabs/prysm`
 2. cd prysm
-3. `docker run -it -v $(pwd):/workdir suburbandad/cross-clang-10:latest` 
+3. `docker run -it -v $(pwd):/workdir suburbandad/prysm-cross:latest` 
 
 From here you can run builds inside the linux x86_64 container image, e.g.:
 
@@ -28,18 +28,14 @@ From here you can run builds inside the linux x86_64 container image, e.g.:
 | arm64   | linux   | linux_arm64   |  Y       | `bazel build --config=linux_arm64_docker //beacon-chain` |
 | x86_64  | linux   | linux_amd64   |  Y       | `bazel build --config=linux_amd64_docker //beacon-chain` |
 | x86_64  | osx     | osx_amd64     |  Y       | `bazel build --config=osx_amd64_docker //beacon-chain` |
-| x86_64  | windows | windows_amd64 |  N       | `bazel build --config=windows_amd64_docker //beacon-chain` |
+| x86_64  | windows | windows_amd64 |  y       | `bazel build --config=windows_amd64_docker //beacon-chain` |
 
 
 #### Or, if you just want to run a particular target, this is handy:
 For example, to build the beacon chain for linux_arm64: 
-`docker run -it -v $(pwd):/workdir suburbandad/cross-clang-10:latest bazel build --config=linux_arm64 //beacon-chain`
+`docker run -it -v $(pwd):/workdir suburbandad/prysm-cross:latest bazel build --config=linux_arm64 //beacon-chain`
 
 
-Also fun, if you are on OSX can build and run a linux_amd64 beacon-chain:
-`docker run -it -v $(pwd):/workdir suburbandad/cross-clang-10:latest bazel run //beacon-chain` 
-            
-
-### Coming soon
-* Windows x86_64 builds
+Also fun, if you are on OSX or windows, you can build and run a linux_amd64 beacon-chain:
+`docker run -it -v $(pwd):/workdir suburbandad/prysm-cross:latest bazel run //beacon-chain`