wget -c https://releases.linaro.org/components/toolchain/binaries/5.2-2015.11/arm-linux-gnueabihf/gcc-linaro-5.2-2015.11-x86_64_arm-linux-gnueabihf.tar.xz
tar Jxf gcc-linaro-5.2-2015.11-x86_64_arm-linux-gnueabihf.tar.xz
./gcc-linaro-5.2-2015.11-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf-gcc --sysroot=./gcc-linaro-5.2-2015.11-x86_64_arm-linux-gnueabihf/arm-linux-gnueabihf/libc/arm-linux-gnueabihf/ main.c -o main
Looks like this will expect libc to be located at /lib/ld-linux-armhf.so.3 so this wouldn't work with the alpine linux distro. You could work around this by compiling with -static like:
export CCC=./gcc-linaro-5.2-2015.11-x86_64_arm-linux-gnueabihf
${CCC}/bin/arm-linux-gnueabihf-gcc --sysroot=${CCC}/arm-linux-gnueabihf/libc/arm-linux-gnueabihf/ -static main.c -o main
And like you would expect, the resulting binary format will be arm:
$ file main
main: ELF 32-bit LSB executable, ARM, EABI5 version 1 (GNU/Linux), statically linked, for GNU/Linux 2.6.32, BuildID[sha1]=56074fabef7e04389c1c1cde7c7ba2d329e5ff3d, not stripped
Oh and this binary will work on x86-64 Linux with qemu-arm. You will need to install all the proper cross compiling packages:
sudo apt-get install qemu qemu-user-static binfmt-support
sudo apt-get install gcc-arm-linux-gnueabihf libc6-dev-armhf-cross
sudo apt-get install binutils-arm-linux-gnueabi
To run it, you may need to pass the linker path as well:
qemu-arm -L /usr/arm-linux-gnueabihf/ ./main # or qemu-arm-static