old_contents: {
    "targets": [
      {
          "target_name": "gf",
          "sources": [
              "gf.cpp",
              "<!@(node -p \"require('fs').readdirSync('./gf-complete/src').map(f=>'gf-complete/src/'+f).join(' ')\")",
              #TODO: neon src files if relevant
          ],
          "include_dirs" : [
              "<!(node -e \"require('nan')\")",
              "gf-complete/include"
          ],
          'variables': {
              'have_neon': '<!()'
          },
          "conditions": [
              ['OS == "mac"', {
                  'xcode_settings': {
                      # gcc on the mac builds horribly unoptimized sse code in debug
                      # mode. Since this is rarely going to be debugged, run with full
                      # optimizations in Debug as well as Release.
                      'GCC_OPTIMIZATION_LEVEL': '3',  # -O3
                      'OTHER_CFLAGS': [
                          '-march=native',
                          '-mavx2',
                          '-fPIC -Wall -Wpointer-arith',
                      ],
                     },
                  }
              ],
          ],
      }
    ]
  }
  
new_contents: {
    "targets": [
      {
          "target_name": "gf",
          "sources": [
              "gf.cpp",
              "<!@(node -p \"require('fs').readdirSync('./gf-complete/src').map(f=>'gf-complete/src/'+f).join(' ')\")",
              #TODO: neon src files if relevant
          ],
          "include_dirs" : [
              "<!(node -e \"require('nan')\")",
              "gf-complete/include"
          ],
          'variables': {
              'have_neon': '<!()'
          },
          "conditions": [
              ['OS == "mac"', {
                  'xcode_settings': {
                      # gcc on the mac builds horribly unoptimized sse code in debug
                      # mode. Since this is rarely going to be debugged, run with full
                      # optimizations in Debug as well as Release.
                      'GCC_OPTIMIZATION_LEVEL': '3',  # -O3
                      'OTHER_CFLAGS': [
                          '-march=native',
                          '-mavx2',
                          '-fPIC -Wall -Wpointer-arith',
                      ],
                     },
                  }
              ],
              ['OS == "linux"', {
                  'cflags': [
                      '-O3',
                      '-march=native',
                      '-mavx2',
                      '-fPIC -Wall -Wpointer-arith',
                  ],
              }],
          ],
      }
    ]
  }
  
subject: update for linux