[libc++][ci] Install ccache in the Docker image

This will allow using ccache in the jobs that build Clang, which
should speed up those jobs.

Differential Revision: https://reviews.llvm.org/D150907

diff --git a/libcxx/utils/ci/Dockerfile b/libcxx/utils/ci/Dockerfile
index d5983ea..acceee3 100644 (file)
--- a/libcxx/utils/ci/Dockerfile
+++ b/libcxx/utils/ci/Dockerfile
@@ -38,9 +38,9 @@ ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y bash curl
 
 # Install various tools used by the build or the test suite
-#RUN apt-get update && apt-get install -y ninja-build python3 python3-sphinx python3-distutils python3-psutil git gdb
+#RUN apt-get update && apt-get install -y ninja-build python3 python3-sphinx python3-distutils python3-psutil git gdb ccache
 # TODO add ninja-build once 1.11 is available in Ubuntu, also remove the manual installation.
-RUN apt-get update && apt-get install -y python3 python3-sphinx python3-distutils python3-psutil git gdb
+RUN apt-get update && apt-get install -y python3 python3-sphinx python3-distutils python3-psutil git gdb ccache
 RUN apt-get update && apt-get install -y wget && \
   wget -qO /usr/local/bin/ninja.gz https://github.com/ninja-build/ninja/releases/latest/download/ninja-linux.zip && \
   gunzip /usr/local/bin/ninja.gz && \