• Version: 12.13.0
• Platform: Raspberry Pi 3, Raspbian -
  pi@raspberrypi:~ $ uname -a
  Linux raspberrypi 4.19.75-v7+ Unable to decrypt aes-256-cbc created by PHP  #1270 SMP Tue Sep 24 18:45:11 BST 2019 armv7l GNU/Linux
• Subsystem: V8 linking, (Node linking?)

In order to build NodeJS from scratch on raspbian, libatomic is needed in v8.gyp so that makesnapshot links.

I believe Raspian has an arm6l kernel, even thought the CPU reports as arm7l.

I also understand that arm6l is no longer built as an official binary, and that I should not expect to build without some pain :).

I am testing a change in v8.gyp:
line 796:

        # Platforms that don't have Compare-And-Swap (CAS) support need to link atomic library
        # to implement atomic memory access
        ['v8_current_cpu in ["mips", "mipsel", "mips64", "mips64el", "ppc"]', {
          'link_settings': {
            'libraries': ['-latomic', ],
          },
        }],

to

        # Platforms that don't have Compare-And-Swap (CAS) support need to link atomic library
        # to implement atomic memory access
        ['v8_current_cpu in ["mips", "mipsel", "mips64", "mips64el", "ppc", "arm"]', {
          'link_settings': {
            'libraries': ['-latomic', ],
          },
        }],

I am no expert on this, so I'm not sure that including "arm" covers too many platforms....

Compilation now continues - I will report final results in some hours (build is slow on RPi...).

Failure was when linking v8's mksnapshot.

I also note that the NodeJS makefiles also lack -latomic, and so have temporarily modified node.gyp to enable it:
line 295:

      ['(OS=="linux" or OS=="mac")', {
        'libraries': ['-latomic'],
      }],

to

      ['(OS=="linux" or OS=="mac") and llvm_version!=0', {
        'libraries': ['-latomic'],
      }],

I know this is an unsuitable mod - Advice on a better cross platform mod appreciated.

p.s. the armv7 binary runs happily on Raspbian on RPi3 - but is unlikely to work on RPiZero or Rpi1 (please correct me if I am wrong...)? There are millions of these devices out in the wild, and continued NodeJS support for them would be nice - e.g. for Node-Red use.