speed up cmake, rustc, openvpn

docker.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -xe
+
+cmake --build build -j 12
+
+cat << EOF > Dockerfile
+FROM debian:trixie-slim
+
+RUN apt update -y && apt install -y --no-install-recommends gcc g++ libc6-dev ca-certificates
+RUN apt remove -y --allow-remove-essential perl manpages-dev perl-base && apt autoremove -y
+
+WORKDIR /app
+CMD ["/bin/bash"]
+EOF
+
+docker build -t shrap .
+rm Dockerfile
+
+docker run --rm -it -v .:/app shrap