linkers: skip -export_dynamic flag before MacOS 10.7

The flag was only introduced in ld 224.1, as mentioned in the initial PR
#13291.

Resolves #13543

(cherry picked from commit 7280639)

mesonbuild/linkers/linkers.py

@@ -837,7 +837,9 @@ def get_thinlto_cache_args(self, path: str) -> T.List[str]:
         return ["-Wl,-cache_path_lto," + path]
 
     def export_dynamic_args(self, env: 'Environment') -> T.List[str]:
-        return self._apply_prefix('-export_dynamic')
+        if mesonlib.version_compare(self.version, '>=224.1'):
+            return self._apply_prefix('-export_dynamic')
+        return []
 
 
 class LLVMLD64DynamicLinker(AppleDynamicLinker):

unittests/darwintests.py

@@ -4,10 +4,11 @@
 import subprocess
 import re
 import os
+import platform
 import unittest
 
 from mesonbuild.mesonlib import (
-    MachineChoice, is_osx
+    MachineChoice, is_osx, version_compare
 )
 from mesonbuild.compilers import (
     detect_c_compiler
@@ -81,6 +82,7 @@ def test_apple_bitcode_modules(self):
         self.build()
         self.run_tests()
 
+    @unittest.skipIf(version_compare(platform.mac_ver()[0], '<10.7'), '-export_dynamic was added in 10.7')
     def test_apple_lto_export_dynamic(self):
         '''
         Tests that -Wl,-export_dynamic is correctly added, when export_dynamic: true is set.