Add new platform aarch64-mingw-ucrt aka Windows on ARM

It fits to the latest RubyInstaller release:
  https://rubyinstaller.org/2025/01/19/rubyinstaller-3.4.1-2-released.html

Fixes #148

Author: larskanis

Diff for: .github/workflows/ci.yml

@@ -53,6 +53,7 @@ jobs:
           - platform: arm-linux-musl
           - platform: arm64-darwin
           - platform: jruby
+          - platform: aarch64-mingw-ucrt
           - platform: x64-mingw-ucrt
             static: true
           - platform: x64-mingw32

Diff for: .github/workflows/publish-images.yml

@@ -13,6 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         platform:
+          - aarch64-mingw-ucrt
           - aarch64-linux-gnu
           - aarch64-linux-musl
           - arm-linux-gnu

Diff for: .github/workflows/release-images.yml

@@ -20,6 +20,7 @@ jobs:
       fail-fast: false
       matrix:
         platform:
+          - aarch64-mingw-ucrt
           - aarch64-linux-gnu
           - aarch64-linux-musl
           - arm-linux-gnu

Diff for: Dockerfile.mri.erb

@@ -24,6 +24,13 @@ COPY --from=larskanis/mingw64-ucrt:20.04 \
     /debs/
 RUN dpkg -i /debs/*.deb
 
+<% elsif platform =~ /aarch64-mingw-ucrt/ %>
+RUN wget https://github.com/mstorsjo/llvm-mingw/releases/download/20250114/llvm-mingw-20250114-ucrt-ubuntu-20.04-#{RUBY_PLATFORM[/^\w+/]}.tar.xz && \
+    tar xf llvm-mingw*.tar.xz && \
+    export MINGW_PATH=`ls -d llvm-mingw-*/` && \
+    echo "export PATH=`pwd`/$MINGW_PATH/bin:\$PATH" >> /etc/rubybashrc && \
+    rm -r $MINGW_PATH/bin/i686-w64* $MINGW_PATH/bin/armv7-w64* $MINGW_PATH/bin/x86_64-w64* $MINGW_PATH/i686-w64* $MINGW_PATH/armv7-w64* $MINGW_PATH/x86_64-w64*
+
 <% elsif platform =~ /linux-musl/ %>
 COPY build/mk_musl_cross.sh /tmp
 RUN /tmp/mk_musl_cross.sh <%= target %>
@@ -117,6 +124,10 @@ xrubies_build_plan = if platform =~ /x64-mingw-ucrt/
     # Rubyinstaller-3.1+ is platform x64-mingw-ucrt
     ["3.4.1:3.3.5:3.2.6:3.1.6", "3.1.6"],
   ]
+elsif platform =~ /aarch64-mingw-ucrt/
+  [
+    ["3.4.1", "3.1.6"],
+  ]
 elsif platform =~ /x64-mingw32/
   [
     # Rubyinstaller prior to 3.1 is platform x64-mingw32
@@ -130,7 +141,7 @@ else
   ]
 end
 
-strip = '-s' if platform !~ /darwin/
+strip = '-s' if platform !~ /darwin|aarch64-mingw/
 
 xrubies_build_plan.each do |xrubies, bootstrap_ruby_version| %>
 RUN bash -c " \
@@ -186,7 +197,7 @@ RUN find /usr/local/rake-compiler/ruby/*/*/lib/ruby -name rbconfig.rb | while re
 ##
 USER root
 
-<% if platform =~ /mingw/ %>
+<% if platform =~ /(x64|x86)-mingw/ %>
 # Install wrappers for strip commands as a workaround for "Protocol error" in boot2docker.
 COPY build/strip_wrapper_vbox /root/
 RUN mv /usr/bin/<%= target %>-strip /usr/bin/<%= target %>-strip.bin && \

Diff for: Rakefile

@@ -15,6 +15,7 @@ platforms = [
   ["arm-linux-gnu", "arm-linux-gnueabihf"],
   ["arm-linux-musl", "arm-linux-musleabihf"],
   ["arm64-darwin", "aarch64-apple-darwin"],
+  ["aarch64-mingw-ucrt", "aarch64-w64-mingw32"],
   ["x64-mingw-ucrt", "x86_64-w64-mingw32"],
   ["x64-mingw32", "x86_64-w64-mingw32"],
   ["x86-linux-gnu", "i686-linux-gnu"],