Merge pull request sigp#3546 from divagant-martian/cross-update

Update cross to install protoc

Cross.toml

@@ -1,5 +1,5 @@
 [target.x86_64-unknown-linux-gnu]
-pre-build = ["apt-get install -y cmake clang-3.9"]
+dockerfile = './scripts/cross/x86_64-unknown-linux-gnu.dockerfile'
 
 [target.aarch64-unknown-linux-gnu]
-pre-build = ["apt-get install -y cmake clang-3.9"]
+dockerfile = './scripts/cross/aarch64-unknown-linux-gnu.dockerfile'

scripts/cross/aarch64-unknown-linux-gnu.dockerfile

@@ -0,0 +1,14 @@
+ARG CROSS_BASE_IMAGE
+FROM $CROSS_BASE_IMAGE
+
+RUN apt-get update -y && apt-get upgrade -y
+
+RUN apt-get install -y unzip && \
+    PB_REL="https://github.com/protocolbuffers/protobuf/releases" && \
+    curl -L $PB_REL/download/v3.15.8/protoc-3.15.8-linux-aarch_64.zip -o protoc.zip && \
+    unzip protoc.zip -d /usr && \
+    chmod +x /usr/bin/protoc
+
+RUN apt-get install -y cmake clang-3.9
+
+ENV PROTOC=/usr/bin/protoc

scripts/cross/x86_64-unknown-linux-gnu.dockerfile

@@ -0,0 +1,14 @@
+ARG CROSS_BASE_IMAGE
+FROM $CROSS_BASE_IMAGE
+
+RUN apt-get update -y && apt-get upgrade -y
+
+RUN apt-get install -y unzip && \
+    PB_REL="https://github.com/protocolbuffers/protobuf/releases" && \
+    curl -L $PB_REL/download/v3.15.8/protoc-3.15.8-linux-x86_64.zip -o protoc.zip && \
+    unzip protoc.zip -d /usr && \
+    chmod +x /usr/bin/protoc
+
+RUN apt-get install -y cmake clang-3.9
+
+ENV PROTOC=/usr/bin/protoc