Use llvm-objcopy/llvm-strip instead of a shell script wrapper and binutils

Dockerfile.dev

@@ -119,12 +119,3 @@ RUN cd test && \
     for arch in $TOOLCHAIN_ARCHS; do \
         cp $TOOLCHAIN_PREFIX/$arch-w64-mingw32/bin/*.dll $arch || exit 1; \
     done
-
-# Cheating: Pull strip and objcopy from the normal binutils package.
-RUN apt-get update -qq && \
-    apt-get install -qqy binutils-mingw-w64-x86-64 && \
-    cp /usr/bin/x86_64-w64-mingw32-strip $TOOLCHAIN_PREFIX/bin/binutils-strip && \
-    cp /usr/bin/x86_64-w64-mingw32-objcopy $TOOLCHAIN_PREFIX/bin/binutils-objcopy && \
-    apt-get remove -qqy binutils-mingw-w64-x86-64 && \
-    apt-get clean -y && \
-    rm -rf /var/lib/apt/lists/*