Compilation / linker error on Arch Linux (running on Pi)

[nb-programmer]

Due to a change in gcc, a flag needs to be added while compiling the code (see https://www.raspberrypi.org/forums/viewtopic.php?t=244375):
CFLAGS=-fcommon

otherwise, the install fails with a linking error:

/usr/bin/ld: build/temp.linux-aarch64-3.9/source/constants.o:/tmp/pip-req-build-q65ingrr/source/common.h:41: multiple definition of module_setup'; build/temp.linux-aarch64-3.9/source/common.o:/tmp/pip-req-build-q65ingrr/source/common.h:41: first defined here /usr/bin/ld: build/temp.linux-aarch64-3.9/source/constants.o:/tmp/pip-req-build-q65ingrr/source/common.h:40: multiple definition of setup_error'; build/temp.linux-aarch64-3.9/source/common.o:/tmp/pip-req-build-q65ingrr/source/common.h:40: first defined here
[snip]

So to install the package, the command would be:
CFLAGS=-fcommon pip install git+https://github.com/TheNextLVL/RPi.GPIO.64.git

Or even better, add extra command line args to the Extension in setup.py:
ext_modules = [Extension('RPi._GPIO', ..., extra_compile_args = ['-fcommon'])]