Use single script for both Dockerfiles

Author: mati865

src/ci/docker/host-x86_64/dist-aarch64-windows-gnullvm/Dockerfile

@@ -14,7 +14,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     python3 \
     xz-utils
 
-COPY host-x86_64/dist-aarch64-windows-gnullvm/install-llvm-mingw.sh /build
+ENV ARCH=aarch64
+COPY host-x86_64/dist-x86_64-windows-gnullvm/install-llvm-mingw.sh /build
 RUN ./install-llvm-mingw.sh
 
 COPY scripts/sccache.sh /scripts/

src/ci/docker/host-x86_64/dist-aarch64-windows-gnullvm/install-llvm-mingw.sh

@@ -14,6 +14,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     python3 \
     xz-utils
 
+ENV ARCH='i686 x86_64'
 COPY host-x86_64/dist-x86_64-windows-gnullvm/install-llvm-mingw.sh /build
 RUN ./install-llvm-mingw.sh
 

src/ci/docker/host-x86_64/dist-x86_64-windows-gnullvm/Dockerfile

@@ -8,6 +8,6 @@ curl -L https://github.com/mstorsjo/llvm-mingw/releases/download/${release_date}
 tar --extract --xz --strip 1 --directory /usr/local
 
 # https://github.com/mstorsjo/llvm-mingw/issues/493
-for arch in i686 x86_64; do
+for arch in $ARCH; do
     ln -s $arch-w64-windows-gnu.cfg /usr/local/bin/$arch-pc-windows-gnu.cfg
 done