build: fix gcc 3.x build

Detect gcc version, -fvisibility is a gcc 4.x switch.

build/gcc_version.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+
+import os
+import re
+import subprocess
+import sys
+
+
+def DoMain(*args):
+  cc = os.environ.get('CC', 'gcc')
+  stdin, stderr = os.pipe()
+  subprocess.call([cc, '-v'], stderr=stderr)
+  output = os.read(stdin, 4096)
+  match = re.search("\ngcc version (\d+\.\d+\.\d+)", output)
+  if match:
+    print(match.group(1))
+
+
+if __name__ == '__main__':
+  DoMain(*sys.argv)

common.gypi

@@ -114,6 +114,9 @@
         ],
       }],
       [ 'OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris"', {
+        'variables': {
+          'gcc_version%': '<!(python build/gcc_version.py)>)',
+        },
         'cflags': [ '-Wall', '-pthread', ],
         'cflags_cc': [ '-fno-rtti', '-fno-exceptions' ],
         'ldflags': [ '-pthread', ],
@@ -125,7 +128,7 @@
           [ 'OS=="linux"', {
             'cflags': [ '-ansi' ],
           }],
-          [ 'visibility=="hidden"', {
+          [ 'visibility=="hidden" and gcc_version >= "4.0.0"', {
             'cflags': [ '-fvisibility=hidden' ],
           }],
         ],