docker: add back CMake for the images used in Cirrus

build_tools/check.sh would give more coverage (the translation
checks is the main difference) but it tests embed-data builds;
for now testing, traditionally installed builds is more important
(especially since I always test check.sh locally already). In future
we will probably make embedding mandatory and get rid of this schism.

docker/alpine.Dockerfile

@@ -6,6 +6,7 @@ ENV LC_ALL=C.UTF-8
 ENV PIP_ROOT_USER_ACTION=ignore
 
 RUN apk add --no-cache \
+    cmake ninja \
     bash \
     cargo \
     g++ \

docker/focal-arm64.Dockerfile

@@ -7,6 +7,7 @@ ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update \
   && apt-get -y install --no-install-recommends \
+    cmake ninja-build \
     build-essential \
     ca-certificates \
     cargo \

docker/jammy-armv7-32bit.Dockerfile

@@ -7,6 +7,7 @@ ENV DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update \
   && apt-get -y install --no-install-recommends  \
+    cmake ninja-build \
     build-essential \
     ca-certificates \
     cargo \

docker/jammy.Dockerfile

@@ -6,6 +6,7 @@ ENV LC_ALL=C.UTF-8
 
 RUN apt-get update \
   && apt-get -y install --no-install-recommends  \
+    cmake ninja-build \
     build-essential \
     ca-certificates \
     cargo \