How to Cross-Compile a Autotools Project for Arm

Cross-compiling for ARM with Autoconf

So I knew I've cross compiled before using really basic method calls and I figured out why I've gotten away with this before after examining the output:

checking for arm-linux-gnueabi-gcc... no
checking for gcc... gcc
...
...
checking for arm-linux-gnueabi-gcc... gcc

In my /usr/bin there was no arm-linux-gnueabi-gcc, I had to:

ln -s /usr/bin/arm-linux-gnueabi-gcc-4.5 /usr/bin/arm-linux-gnueabi-gcc

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I successfully cross-compiled using:

./configure --host=arm-linux-gnueabi -prefix=${CSTOOL_DIR}/linux_arm_tool

as for linking ... I still have to check some things, but I am going to assume I might need to throw some -rpath-link flags in more advanced compiles.

Cross Compile a automake project?

you don't have to change anything. autotools comes with full cross-compilation support.

Just pass the proper --host= flag for your target architecture, e.g.:

./configure --host arm-linux-gnueabihf

This will look for toolchain programs with the given prefix (in the above case, it would look e.g. for a compiler arm-linux-gnueabihf-gcc) in your current $PATH. Most cross-compiling toolchains should automatically adhere to this convention.

See also the official documentation

autotools, how to fail if cross compiler cannot be found

When you specify --host=<host-type>, and this value differs from the result of running the config.guess script, autoconf enters cross-compilation mode. Specifically, the variable cross_compiling is set to yes.

If the configure script is in 'cross-compilation' mode, it can't run any resulting executable, so there's no way to tell if a resulting binary is a valid 'host' binary or not. Presumably, a large database of file magic values might be able to tell if a valid host binary has been generated. Despite a couple of decades worth of experience built into the autotools, there are some combinatorial problems that can never keep up with all possible architectures and ABIs.

The autoconf C compiler tests check to see if the compiler - that is $CC - can build an executable. autoconf may provide a warning if the compiler is not prefixed with the host triplet, e.g., arm-none-eabi-gcc, but will not 'fail' if it finds a working compiler, such as the native gcc.

So, the only way to ensure cross-compilation with the correct compiler is to specify the compiler:

./configure --host=arm-none-eabi CC="arm-none-eabi-gcc"

If this compiler can't build executables, the configure script will fail.

How to install dependencies for a project that is being cross-compiled on an x86 host for an arm target

@artless-noise guides were a good jumping off point, but unfortunately most of the guides weren't helpful in accomplishing what I wanted to do (or if they were, they weren't straightforward in explaining how to accomplish what I needed).

What I ended up doing was using qemu-debootstrap

sudo qemu-debootstrap --arch armhf buster /mnt/data/armhf http://deb.debian.org/debian/

And then just using sudo chroot /mnt/data/armhf and I had a functioning shell where I could just apt-get anything I needed, run any scripts and get armhf binaries.

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