Dockerfile: update base images

Author: tsl0922

Dockerfile

@@ -1,5 +1,6 @@
-FROM tsl0922/musl-cross
-RUN git clone --depth=1 https://github.com/tsl0922/ttyd.git /ttyd \
+FROM ubuntu:18.04
+RUN apt-get update && apt-get install -y autoconf automake curl cmake git libtool make \
+    && git clone --depth=1 https://github.com/tsl0922/ttyd.git /ttyd \
     && cd /ttyd && env BUILD_TARGET=x86_64 WITH_SSL=true ./scripts/cross-build.sh
 
 FROM ubuntu:18.04
@@ -9,6 +10,7 @@ ADD https://github.com/krallin/tini/releases/download/v0.18.0/tini /sbin/tini
 RUN chmod +x /sbin/tini
 
 EXPOSE 7681
+WORKDIR /root
 
 ENTRYPOINT ["/sbin/tini", "--"]
 CMD ["ttyd", "bash"]

Dockerfile-alpine

@@ -1,12 +1,14 @@
-FROM tsl0922/musl-cross
-RUN git clone --depth=1 https://github.com/tsl0922/ttyd.git /ttyd \
+FROM ubuntu:18.04
+RUN apt-get update && apt-get install -y autoconf automake curl cmake git libtool make \
+    && git clone --depth=1 https://github.com/tsl0922/ttyd.git /ttyd \
     && cd /ttyd && env BUILD_TARGET=x86_64 WITH_SSL=true ./scripts/cross-build.sh
 
-FROM alpine:3.10
+FROM alpine:3.12
 COPY --from=0 /ttyd/build/ttyd /usr/bin/ttyd
 RUN apk add --no-cache bash tini
 
 EXPOSE 7681
+WORKDIR /root
 
 ENTRYPOINT ["/sbin/tini", "--"]
 CMD ["ttyd", "bash"]