use a common definition of NULL as 0L for C and C++
[musl] / arch /
drwxr-xr-x   ..
drwxr-xr-x - arm
drwxr-xr-x - i386
drwxr-xr-x - microblaze
drwxr-xr-x - mips
drwxr-xr-x - powerpc
drwxr-xr-x - x86_64