ci: Add Rust Windows cross toolchain on ubuntu-rolling image

ci/ciimage/build.py

@@ -74,6 +74,12 @@ class Builder(BuilderBase):
         # Also add /ci to PATH
         out_data += 'export PATH="/ci:$PATH"\n'
 
+        out_data += '''
+            if [ -f "$HOME/.cargo/env" ]; then
+                source "$HOME/.cargo/env"
+            fi
+        '''
+
         out_file.write_text(out_data, encoding='utf-8')
 
         # make it executable

ci/ciimage/ubuntu-rolling/install.sh

@@ -50,6 +50,13 @@ dub_fetch dubtestproject
 dub build dubtestproject:test1 --compiler=ldc2
 dub build dubtestproject:test2 --compiler=ldc2
 
+# Remove debian version of Rust and install latest with rustup.
+# This is needed to get the cross toolchain as well.
+apt-get -y remove rustc || true
+wget -O - https://sh.rustup.rs | sh -s -- -y --profile minimal --component clippy
+source "$HOME/.cargo/env"
+rustup target add x86_64-pc-windows-gnu
+
 # cleanup
 apt-get -y clean
 apt-get -y autoclean