Add base build image

base/Dockerfile

@@ -0,0 +1,11 @@
+FROM ubuntu:20.04
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN \
+    apt-get -y update && \
+    apt-get -y dist-upgrade && \
+    apt-get -y install build-essential yasm nasm pkg-config git curl wget cmake unzip subversion autoconf automake libtool clang && \
+    apt-get -y clean
+
+RUN mkdir -p /opt/ffbuild/{lib,bin,include}