automatically add _32 and _64 prefix to executable

Makefile

@@ -1,4 +1,10 @@
-all: mtxrpicam
+ifeq ($(shell gcc -dumpmachine),aarch64-linux-gnu)
+  EXECUTABLE_NAME = mtxrpicam_64
+else
+  EXECUTABLE_NAME = mtxrpicam_32
+endif
+
+all: $(EXECUTABLE_NAME)
 
 #################################################
 # text font
@@ -64,5 +70,5 @@ DEPENDENCIES = \
 %.o: %.cpp $(DEPENDENCIES)
 	$(CXX) $(CXXFLAGS) -c $< -o $@
 
-mtxrpicam: $(OBJS)
+$(EXECUTABLE_NAME): $(OBJS)
 	$(CXX) $^ $(LDFLAGS) -o $@

README.md

@@ -29,7 +29,7 @@ This is embedded into all MediaMTX releases and shouldn't normally be downloaded
    make -j$(nproc)
    ```
 
-4. The resulting executable will be available in `mtxrpicam`
+   This will produce `mtxrpicam_32` or `mtxrpicam_64` (depending on the architecture).
 
 ## Cross-compile
 
@@ -43,15 +43,15 @@ This is embedded into all MediaMTX releases and shouldn't normally be downloaded
    make -f utils.mk build
    ```
 
-4. The resulting executables will be available in `mtxrpicam_32` and `mtxrpicam_64`
+   This will produce `mtxrpicam_32` and `mtxrpicam_64`.
 
 ## Installation
 
 1. Download MediaMTX source code and open a terminal in it
 
 2. Run `go generate ./...`
 
-3. Copy `mtxrpicam` inside `internal/staticsources/rpicamera/mtxrpicam_64` (if the Raspberry Pi OS is 64-bit) or inside `internal/staticsources/rpicamera/mtxrpicam_32` (if the Raspberry Pi OS is 32-bit)
+3. Copy `mtxrpicam_32` and/or `mtxrpicam_64` inside `internal/staticsources/rpicamera/`
 
 4. Compile MediaMTX
 

utils.mk

@@ -1,4 +1,3 @@
-ALPINE_IMAGE = alpine:3.20
 RPI32_IMAGE = balenalib/raspberry-pi:bullseye-run-20240508
 RPI64_IMAGE = balenalib/raspberrypi3-64:bullseye-run-20240429
 
@@ -16,9 +15,13 @@ help:
 
 build: build32 build64
 
+enable_multiarch:
+	docker run --rm --privileged multiarch/qemu-user-static:register --reset --credential yes
+
 define DOCKERFILE_BUILD32
+FROM multiarch/qemu-user-static:x86_64-arm AS qemu
 FROM $(RPI32_IMAGE) AS build
-RUN ["cross-build-start"]
+COPY --from=qemu /usr/bin/qemu-arm-static /usr/bin/qemu-arm-static
 RUN apt update && apt install -y --no-install-recommends \
 	g++ \
 	pkg-config \
@@ -30,18 +33,17 @@ RUN apt update && apt install -y --no-install-recommends \
 WORKDIR /s
 COPY . .
 RUN make -j$$(nproc)
-FROM $(ALPINE_IMAGE)
-COPY --from=build /s/mtxrpicam /s/mtxrpicam
 endef
 export DOCKERFILE_BUILD32
 
-build32:
+build32: enable_multiarch
 	echo "$$DOCKERFILE_BUILD32" | docker build . -f - -t build32
-	docker run --rm -v $(PWD):/o build32 sh -c "mv /s/mtxrpicam /o/mtxrpicam_32"
+	docker run --rm -v $(PWD):/o build32 sh -c "mv /s/mtxrpicam_32 /o/"
 
 define DOCKERFILE_BUILD64
+FROM multiarch/qemu-user-static:x86_64-aarch64 AS qemu
 FROM $(RPI64_IMAGE) AS build
-RUN ["cross-build-start"]
+COPY --from=qemu /usr/bin/qemu-aarch64-static /usr/bin/qemu-aarch64-static
 RUN apt update && apt install -y --no-install-recommends \
 	g++ \
 	pkg-config \
@@ -53,14 +55,12 @@ RUN apt update && apt install -y --no-install-recommends \
 WORKDIR /s
 COPY . .
 RUN make -j$$(nproc)
-FROM $(ALPINE_IMAGE)
-COPY --from=build /s/mtxrpicam /s/mtxrpicam
 endef
 export DOCKERFILE_BUILD64
 
-build64:
+build64: enable_multiarch
 	echo "$$DOCKERFILE_BUILD64" | docker build . -f - -t build64
-	docker run --rm -v $(PWD):/o build64 sh -c "mv /s/mtxrpicam /o/mtxrpicam_64"
+	docker run --rm -v $(PWD):/o build64 sh -c "mv /s/mtxrpicam_64 /o/"
 
 define DOCKERFILE_TEST32
 FROM multiarch/qemu-user-static:x86_64-arm AS qemu
@@ -70,8 +70,7 @@ RUN apt update && apt install -y --no-install-recommends libcamera0 libfreetype6
 endef
 export DOCKERFILE_TEST32
 
-test32:
-	docker run --rm --privileged multiarch/qemu-user-static:register --reset --credential yes
+test32: enable_multiarch
 	echo "$$DOCKERFILE_TEST32" | docker build . -f - -t test32
 	docker run --rm --platform=linux/arm/v6 -v $(PWD):/s -w /s test32 bash -c "TEST=1 ./mtxrpicam_32"
 
@@ -83,7 +82,6 @@ RUN apt update && apt install -y --no-install-recommends libcamera0 libfreetype6
 endef
 export DOCKERFILE_TEST64
 
-test64:
-	docker run --rm --privileged multiarch/qemu-user-static:register --reset --credential yes
+test64: enable_multiarch
 	echo "$$DOCKERFILE_TEST64" | docker build . -f - -t test64
 	docker run --rm --platform=linux/arm64/v8 -v $(PWD):/s -w /s test64 bash -c "TEST=1 ./mtxrpicam_64"