Fix VM setup

Author: antoyo

.github/workflows/m68k.yml

@@ -1,6 +1,3 @@
-# How to chroot with qemu into a Debian created with debootstrap: https://unix.stackexchange.com/questions/41889/how-can-i-chroot-into-a-filesystem-with-a-different-architechture
-# Commands need to be run inside qemu-m68k-static, e.g. qemu-m68k-static /usr/bin/ls.
-#
 # TODO: check if qemu-user-static-binfmt is needed (perhaps to run some tests since it probably calls exec).
 
 name: m68k CI
@@ -108,6 +105,12 @@ jobs:
         #path: rust
         #key: ${{ runner.os }}-packages-${{ hashFiles('rust/.git/HEAD') }}
 
+    - name: Prepare VM
+      run: |
+        mkdir vm
+        sudo mount debian-m68k.img vm
+        sudo cp $(which qemu-m68k-static) vm/usr/bin/
+
     - name: Build
       run: |
         ./y.sh prepare --only-libcore --cross

Readme.md

@@ -321,12 +321,10 @@ generate it in [gimple.md](./doc/gimple.md).
 
 #### Configuring rustc_codegen_gcc
 
- * Set `TARGET_TRIPLE="m68k-unknown-linux-gnu"` in config.sh.
- * Since rustc doesn't support this architecture yet, set it back to `TARGET_TRIPLE="mips-unknown-linux-gnu"` (or another target having the same attributes). Alternatively, create a [target specification file](https://book.avr-rust.com/005.1-the-target-specification-json-file.html) (note that the `arch` specified in this file must be supported by the rust compiler).
  * Run `./y.sh prepare --cross` so that the sysroot is patched for the cross-compiling case.
+ * If the target is not yet supported by the Rust compiler, create a [target specification file](https://book.avr-rust.com/005.1-the-target-specification-json-file.html) (note that the `arch` specified in this file must be supported by the rust compiler).
  * Set `linker='-Clinker=m68k-linux-gcc'`.
  * Set the path to the cross-compiling libgccjit in `gcc_path`.
- * (might not be necessary) Disable the compilation of libstd.so (and possibly libcore.so?): Remove dylib from build_sysroot/sysroot_src/library/std/Cargo.toml.
 
 If you get the following error: