Restructure the readme wrt the use of docker

README.md

@@ -33,24 +33,6 @@ To build, just do:
 This will download and build all parts of the toolchain, and build a few
 demo apps to show and verify that the toolchain works.
 
-The produced toolchain can be extracted by running this command with the
-image id from the `docker build` command above (ending with e.g.
-`Successfully built d8b13aad965a`):
-
-    ./extract-docker.sh d8b13aad965a prefix
-
-This copies the directory `prefix` (which contains the whole toolchain,
-with headers and link libraries for all four architectures) from the
-built docker image into the current directory.
-The Dockerfile currently builds in an Ubuntu 16.04 environment, so the
-extracted toolchain can at least be used in such an environment.
-
-The extracted toolchain can be used by adding `prefix/bin` to `$PATH`
-and calling e.g. `x86_64-w64-ming32-clang`.
-(If using the extracted toolchain in an environment that already have
-got a normal GCC based MinGW toolchain with the same triplet prefix in
-the same path, you may need to add
-`--sysroot=path/to/prefix/x86_64-w64-mingw32` to the clang commands.)
 
 Other branches in this repo contain patches that might not have been
 merged upstream yet, and tests of building third party projects using
@@ -59,6 +41,11 @@ usual binutils names, to allow using it as a drop-in replacement for
 a normal MinGW toolchain.
 
 
+If the toolchain is used in an environment that already have got a
+normal GCC based MinGW toolchain with the same triplet prefix in
+the same path, you may need to add
+`--sysroot=path/to/prefix/x86_64-w64-mingw32` to the clang commands.
+
 Status
 ------
 
@@ -87,3 +74,32 @@ normal GCC/binutils based MinGW.
 - The ARM64 target doesn't support thread local variables.
 
 Additionally, one may run into other minor differences between GCC and clang.
+
+
+Use outside of Docker
+---------------------
+
+To use a similar toolchain outside of Docker, you can run the same build
+commands as the dockerfile in probably most recent linux distributions.
+The build procedure is currently only maintained as a Dockerfile, for ease
+of verification, reproducibility and ease of maintainance though.
+
+The toolchain that was built within the docker image can also be
+extracted from the image into the surrounding host environment.
+The `extract-docker.sh` script can copy out a directory from a
+built docker image, either for getting the toolchain or built test
+binaries, when given a docker tag or image id.
+
+If the `docker build` command ended with e.g.
+`Successfully built d8b13aad965a`, you can run:
+
+    ./extract-docker.sh d8b13aad965a prefix
+
+This copies the directory `prefix` (which contains the whole toolchain,
+with headers and link libraries for all four architectures) from the
+built docker image into the current directory.
+The Dockerfile currently builds in an Ubuntu 16.04 environment, so the
+extracted toolchain can at least be used in such an environment.
+
+The extracted toolchain can be used by adding `prefix/bin` to `$PATH`
+and calling e.g. `x86_64-w64-ming32-clang`.