bindings: expose Linkage to the python bindings

Add Python bindings for the 'clang_getCursorLinkage', and tests to
validate the functionality.

Patch by Masud Rahman!

llvm-svn: 314009
diff --git a/clang/bindings/python/tests/cindex/test_linkage.py b/clang/bindings/python/tests/cindex/test_linkage.py
new file mode 100644
index 0000000..2f056d5
--- /dev/null
+++ b/clang/bindings/python/tests/cindex/test_linkage.py
@@ -0,0 +1,30 @@
+
+from clang.cindex import LinkageKind
+from clang.cindex import Cursor
+from clang.cindex import TranslationUnit
+
+from .util import get_cursor
+from .util import get_tu
+
+def test_linkage():
+    """Ensure that linkage specifers are available on cursors"""
+
+    tu = get_tu("""
+void foo() { int no_linkage; }
+static int internal;
+namespace { extern int unique_external; }
+extern int external;
+""", lang = 'cpp')
+
+    no_linkage = get_cursor(tu.cursor, 'no_linkage')
+    assert no_linkage.linkage == LinkageKind.NO_LINKAGE;
+
+    internal = get_cursor(tu.cursor, 'internal')
+    assert internal.linkage == LinkageKind.INTERNAL
+
+    unique_external = get_cursor(tu.cursor, 'unique_external')
+    assert unique_external.linkage == LinkageKind.UNIQUE_EXTERNAL
+
+    external = get_cursor(tu.cursor, 'external')
+    assert external.linkage == LinkageKind.EXTERNAL
+