[K/N] Dockerfile for building LLVM

Provide a stable environment for building LLVM for Linux
by using Docker. Note that the base image is Ubuntu 16.04,
so after LLVM update building Kotlin/Native on Linux will
require glibc 2.23 or higher.

kotlin-native/tools/llvm_builder/Dockerfile

@@ -0,0 +1,25 @@
+FROM ubuntu:16.04
+
+ENV TZ=Europe/Moscow
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
+RUN apt-get update
+RUN apt-get install -y git cmake curl unzip ninja-build gcc g++ build-essential zlib1g-dev
+
+# Build Python.
+RUN cd /opt && \
+    curl -LO https://www.python.org/ftp/python/3.6.9/Python-3.6.9.tgz && \
+    tar -xf Python-3.6.9.tgz && \
+    cd Python-3.6.9 && \
+    ./configure && make && make install
+
+# Create a user.
+ARG USERNAME=jb
+RUN groupadd -g 1000 $USERNAME
+RUN useradd -r -u 1000 --create-home -g $USERNAME $USERNAME
+USER $USERNAME
+WORKDIR /home/$USERNAME
+
+COPY package.py .
+
+ENTRYPOINT ["python3.6", "package.py"]

kotlin-native/tools/llvm_builder/README.md

@@ -30,6 +30,15 @@ Some examples:
   means that LLVM will build itself by using distribution from the previous step.
 * `--stage0` allows using existing LLVM toolchain for bootstrapping.
 
+### Docker
+
+You can use Docker to build LLVM for Linux:
+```shell
+docker build -t kotlin-llvm-builder .
+docker run --rm -it -v <HOST_PATH>:/output kotlin-llvm-builder --archive-path /output/llvm-11.1.0-linux-x64
+
+```
+
 ### Known problems
 1. Bootstrap build is not working on macOS for default git branch.
 2. `libcxx` and `compiler-rt` are built as projects, not runtimes.