ci: use -j 4 for docker jobs

locally you can overload it using `export CMAKE_BUILD_PARALLEL_LEVEL=4`

Author: Mizux

ci/Makefile

@@ -143,6 +143,7 @@ help:
 	@echo
 	@echo -e "\t${BOLD}NOCACHE=1${RESET}: use 'docker build --no-cache' when building container (default use cache)."
 	@echo -e "\t${BOLD}VERBOSE=1${RESET}: use 'docker build --progress=plain' when building container."
+	@echo -e "\t${BOLD}CMAKE_BUILD_PARALLEL_LEVEL=4${RESET}: number of concurrent processes to use when building."
 	@echo
 	@echo -e "branch: $(BRANCH)"
 	@echo -e "sha1: $(SHA1)"
@@ -174,6 +175,10 @@ ifdef VERBOSE
 DOCKER_BUILD_CMD := ${DOCKER_BUILD_CMD} --progress=plain
 DOCKER_BUILDX_CMD := ${DOCKER_BUILDX_CMD} --progress=plain
 endif
+ifdef CMAKE_BUILD_PARALLEL_LEVEL
+DOCKER_BUILD_CMD := ${DOCKER_BUILD_CMD} --build-arg CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL}
+DOCKER_BUILDX_CMD := ${DOCKER_BUILDX_CMD} --build-arg CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL}
+endif
 DOCKER_RUN_CMD := docker run --rm --init --net=host
 
 # Currently supported distro

ci/docker/almalinux/Dockerfile

@@ -16,6 +16,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/alpine/Dockerfile

@@ -11,6 +11,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/archlinux/Dockerfile

@@ -11,6 +11,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/debian/Dockerfile

@@ -15,6 +15,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/fedora/Dockerfile

@@ -15,6 +15,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/opensuse/Dockerfile

@@ -14,6 +14,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/rockylinux/Dockerfile

@@ -16,6 +16,9 @@ FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release

ci/docker/ubuntu/Dockerfile

@@ -10,10 +10,14 @@ RUN apt update -q \
 && apt-get clean \
 && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
+# Add the library src to our build env
 FROM env AS devel
 WORKDIR /home/project
 COPY . .
 
+ARG CMAKE_BUILD_PARALLEL_LEVEL
+ENV CMAKE_BUILD_PARALLEL_LEVEL=${CMAKE_BUILD_PARALLEL_LEVEL:-4}
+
 FROM devel AS build
 RUN cmake --version
 RUN cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release