armv7-linux-deb9: Fix GHC bindist URL

armv7-linux-deb9/Dockerfile

@@ -29,7 +29,7 @@ RUN curl http://releases.llvm.org/$BOOT_LLVM_VERSION/clang+llvm-$BOOT_LLVM_VERSI
 # GHC
 # Use 8.8.1 to bootstrap, since earlier releases are especially buggy on AArch64
 ENV GHC_VERSION 8.8.1
-RUN curl http://home.smart-cactus.org/~ben/ghc/ghc-$GHC_VERSION-arm-unknown-linux.tar.xz | tar -xJ
+RUN curl https://downloads.haskell.org/ghc/$GHC_VERSION/ghc-$GHC_VERSION-armv7l-deb9-linux.tar.xz | tar -xJ
 WORKDIR /ghc-$GHC_VERSION
 RUN ./configure --prefix=/usr/local LLC=$BOOT_LLVM_DIR/bin/llc OPT=$BOOT_LLVM_DIR/bin/opt && \
     make install